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AGENCY FOR INTERNATIONAL DEIVELOPMENT FOR AID USE 0t LLWASHINGTON 0 C20523
A BIBLIOGRAPHIC INPUT SHEET 1-i S U BJ E C T A PRIMARYICLA IJ Food production and nutrition AP12-00000000
A MAJtdfApYFICATION S 2 L A Drainage and irrigation 2S TITLE AND gUBTITLE
Discharge through inclined gates
3 AUTHOR(S)
ChenChia-shyun
4DOCUMENT DATE iS NUMBER OF PAGES 16 ARC NUMBER 1977J 87pARC
7 REFERENCE ORGANIZATION NAME AND ADDRESS ColoState
0 SUPPLEMENTARY NOTES (S)naorlng Otganization PubilihernpAvalability)
(Thesis MS--ColoState)
9 ABSTRACT
Losses of water along irrigation watercourses contribute to low overall irrigationefficiencies in less developed countries This thesis investigates dischargeefficiencies of submerged gates for controlling flow in irrigation watercourses Two types of gates suitable for use as both control and measurement structures weredesigned in Pakistan by the Colorado State University Water Management ResearchGroup Both were made to fit into a channel at a 45 degree inclination so thatgravity would assist in sealing against leakage Hydraulic data was collectedunder free flow and submerged flow conditions for test gates with both circular andrectangular openings The method of submerged flow analysis reported by Villemonte was used in developing the rating curves for the gates These ratings were thencompared with those obtained for vertical weirs in order to observe the effect ofthe 45 degree inclination of the test gates The conclusions mainly expressedmathematically address questions of when and how free-flow weir equations shouldbe applied Recommendations are made regarding further research
10 CONTROL NUMBER
PN-AAD-122
- II PRICE OF DOCUMENT
12 DESCRIPTORS
Equations Flow measurement Hydraulic structures Orifices
Weirs 13 PROJECT NUraER
14 CONTRACT NUMBER CSD-2460 211(d)
is TYPE OF DOCUMENT
AID 5gO- 1(474I
A bA
THESIS
DISCHARGE THROUGH INCLINED GATES
Submitted by
Chia-Shyun Chen
In partial fulfillment of the requirement
for the degree of Master of Science
Colorado State University
Fort Collins Colorado
Spring 1977
ABSTRACT OF THESIS
DISCHARGE THROUGH INCLINED GATES
Fourga1tes one rectangular andthree circular
installed at 45degreesfto the channelbottomAwere investishy
gated The rectangular gate performedtasa-submerged weir
fonly The-circular gates performed as submergedWeirs-when
the upstream water depth was belowtheltop of-the-circular
opening and performed as orifices When the upstream water
depth wasabove the topof the circular opening -Two-kinds
ofnappes surface nappe and plunging nappewereobserved
in the submerged weir flow conditions Weirdischarges under
plunging nappe flow were independent of downstreamwater
depth so these data were used to calibratethe free flow
discharge equations The free flow discharge-coefficient
for the rectangular gate was constant and for the circular
gates was a function of the ratio of upstream head to the
crest height Data for the surface nappe condition were
used to calibrate the submerged flow discharge equations
The submerged flow discharge coefficients for all gates were
functions of submergence ratio and opening configurations
and different by multiplicative constant from reported
coefficient for vertical sharp-crested weirs The discharge
equations for orifice flow were functions of opening configshy
urations
Chia-Shyun Chen Agricultural Engineering DepartmentColorado State University Fort Collins Colorado 80523 Spring 1977
iii
ACKNOWLEDGMENTS
The author wishes to express his sincere thanks to his
adviser Dr William Hart for the time and guidance he put
intothiswork The contributions of-DrEverettrRichardson
and Dr Wynn Walker-are-also appreciated
1 Chi-MeiSpecial thanksilearedue toi the authors wife
who didthe job oftyping the final manuscript1iand encouraged
theauthor all the time
-iThis iwork wassupportedbyfunds from the United States
Agency for International Developm~entunderContract No
AIDcsd-2460 OptimumUtilizatin of WaterResources for
Agriculture with SpeciaLEmphasis on Water Removal and
PDelivery SYStems and Relevant Institutional Development
partia support was also prvvided by USAID Contract
AIDta c-ll00
iv
TABLE OF CONTENTS
ChaptePage
rIST OF - TABLES vii
IST OF FIGURES bull bull A 66 viii
IST OF SYMBOLS- bull X
1 INTRODUCTION bull 1
Purpose 2
Scope bull 2
II DEVELOPMENT OF WEIR AND ORIFICE EQUATIONS 3
General Features 3
Basic Equations for Weirs and Orifices 3
Weir Performance--Submerged
Orifice Equation 4
Weir Equation 7
III DERIVATION OF CIRCULAR WEIR EQUATION 12
Derivation 12
IV SUBMERGED WEIR FLOW ANALYSIS 22
V EXPERIMENT FACILITIES AND GATE GEOMETRIES 29
VI RESULTS AND DISCUSSIONS 36
Results 36
Dimensional Analysis 36 Weir Performance--Free Flow 38
Flow 40 Orifice Performance 45
Discussions 49
Head Measurement 49 The Effect of Submergence Ratio 51 The Discharge Coefficient for
the Inclined Submerged Weir 52
ACKNOWLEDGMENTS
The author wishes to express his sincere thanks-tohis
adviser Dr William Hart for the time anduidance he put t into this work The contributionsf Dr Everett Richardson
and) Dr Wynn Walker are also apprecd6ated
Specia thanksare due tothe-authors wife Chi-Mei
who didthe job oftyping the final manuscript and encouraged
the author-al-l thetime
ThiUsi work was supported by fundsfrom the United States
Agency for International Development under Contract No
AIDcsd-24601 Optimum Utilization of Water Resources for
Agriculture with Special Emphasis on Water Removal and
Delivery Systems and Relevant Institutional Development
Partial support was also provided by USAID Contract
AIDta-c-ll00
iv
LIST OF TABLES
Table Page
1 Values of PL(H1 D) = 11228 (H1D)2
- 2884 (H1D3 462 (H1D)
4
- 8 (HID)5 21
2 Dimensions of Test Gates All Variables Refer to Fig 53 35
3 Discharge Equations for Models Investigated 58
4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m 61
5 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Weir Flow 63
6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Heightof 014 m Orifice Flow 67
7 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Weir Flow 71
8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow 73
9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Weir Flow 75
10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Orifice Flow 77
vii
LIST OF FIGURES
F ePage
21 ree Orifice
6 22 SubmergedJet Orifice
Front View of Flow over a Recta~ngular Weir 823
24 ShrCrested -Weir8
1331 Circular Weir
Curve of Function PL(H1D) = 11228 (H D)2
32 3 - (HID)4 168-2884 (HID) 462 bull 20(H1lD)s
41 Submerged Weir 23
Three Types of Weir Flow (After Vennard) bull bull 2742
51 Plan View of Experimental Facilities 30
52 Illustration of Crest Height for Inclindd 33Gate
34 53 Configurations of Gates
61 Free Flow Discharge Coefficient Cdf for
Circular Gates As a Function of Ratio of Upstream Head to Crest Height H1P
= 0090 - 0080 (HIP) CorrelationCidf Coefficient r =0973 39
Submerged Weir Flow Discharge Coefficient62 Cds for Rectangular Gate with a Crest
Height of 008 m As a Function of 1 - S32 S is the Submergence Ratio
Cds= 2069 (1 - $32)0393 Correlation
42=0987 Coefficient r
Submerged Weir Flow Discharge Coefficient63 Cds for 038 m Diameter Circular Gate with
a Crest Height of 014 m As a Function of
1 - s2 S is the Submergence Ratio
= 1128 ( 2 S2)0385 Correlation
Coefficient = 0990 43
viii
LIST OF FIGURES (Continued)
Figure Page
64 Submerged Weir Flow Discharge Coefficient Cds for 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of
1 - S2 S is the Submergence Ratio Cds = 1062 (1 - $2)0 378 Correlation
Coefficient r2 = 0997 44
65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with
a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio
2)0 3 92ds 1210 (1 - Correlation 2Coefficient r = 0993 46
66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H (H1 - H2 ) Q = 136 H0477
Correlation Coefficient r2 = 0992 47
67 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head
Difference H (H1 - H2 ) Q = 133 H0477
2Correlation Coefficient r = 0989 48
68 Submerged Orifice Flow Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of Head
Difference H (H1 - H2 ) Q = 213 H0475
Correlation Coefficient r2 = 0990 50
ix
ISTOF SYMBOLS
Symbol Definition
A Area of flow at weir notch or orifice L2
A0 Areamp-of flowat vena contracta L2k
B Width of channel L
C Cauchy number-
Cc ontraction coefficient
Cd )ischarge coefficient
Cdf )ischarge coefficient for free flow condition
Cds )ischarge coefficient for submerged flow condition
Cv lelocity coefficient
D Diameter of circular weir L
F Froude number 2
g Acceleration due to gravity LTshy
h Head on an elementary area L
H Head difference H1 - H2 L
H1 Upstream head L
H2 Downstream head L
K Coefficient of submerged weir flow discharge coefficient-see Eq 4-4
L Length of rectangular weir notch L
LI Effective length of contracted weir L
m Exponent of submerged weir flow discharge coefficient see Eq 4-4
n Exponent of weir equations
N Number of end contractions
P Crest height L 1
Q Actual total discharge L3Tshy
V
L13T OF SYMBOLS (Continued)
Symbol Definition
Q1 Ideal total discharge L3T1
Qf Free flow discharge L3T I
Qs Submerged flow discharge L3T 1
r Correlation coefficient
R Radius of circular weir L
Re Reynolds number
S Submergence ratio H2H 1 1Velocity of approach LT-
Va Mean velocity in the channel of approach above the crest level LT I
Vb Mean velocity in the channel of approach below the crest level LT-
Vt Theoretical velocity at weir notch or orificeT-1
W Weber number
Y1 Upstream water depth L
Y2 Downstream water depth L
Coefficient corrects for inequality of velocity in the approach channel
- 2 y Specific weight ML-2T
FE Elastic molulus ML-IT- 2
p Density of mass ML
Surface tension MT 2
a 1
Dynamic viscosity ML-1 Tshy
r Gamma function
xi
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
A bA
THESIS
DISCHARGE THROUGH INCLINED GATES
Submitted by
Chia-Shyun Chen
In partial fulfillment of the requirement
for the degree of Master of Science
Colorado State University
Fort Collins Colorado
Spring 1977
ABSTRACT OF THESIS
DISCHARGE THROUGH INCLINED GATES
Fourga1tes one rectangular andthree circular
installed at 45degreesfto the channelbottomAwere investishy
gated The rectangular gate performedtasa-submerged weir
fonly The-circular gates performed as submergedWeirs-when
the upstream water depth was belowtheltop of-the-circular
opening and performed as orifices When the upstream water
depth wasabove the topof the circular opening -Two-kinds
ofnappes surface nappe and plunging nappewereobserved
in the submerged weir flow conditions Weirdischarges under
plunging nappe flow were independent of downstreamwater
depth so these data were used to calibratethe free flow
discharge equations The free flow discharge-coefficient
for the rectangular gate was constant and for the circular
gates was a function of the ratio of upstream head to the
crest height Data for the surface nappe condition were
used to calibrate the submerged flow discharge equations
The submerged flow discharge coefficients for all gates were
functions of submergence ratio and opening configurations
and different by multiplicative constant from reported
coefficient for vertical sharp-crested weirs The discharge
equations for orifice flow were functions of opening configshy
urations
Chia-Shyun Chen Agricultural Engineering DepartmentColorado State University Fort Collins Colorado 80523 Spring 1977
iii
ACKNOWLEDGMENTS
The author wishes to express his sincere thanks to his
adviser Dr William Hart for the time and guidance he put
intothiswork The contributions of-DrEverettrRichardson
and Dr Wynn Walker-are-also appreciated
1 Chi-MeiSpecial thanksilearedue toi the authors wife
who didthe job oftyping the final manuscript1iand encouraged
theauthor all the time
-iThis iwork wassupportedbyfunds from the United States
Agency for International Developm~entunderContract No
AIDcsd-2460 OptimumUtilizatin of WaterResources for
Agriculture with SpeciaLEmphasis on Water Removal and
PDelivery SYStems and Relevant Institutional Development
partia support was also prvvided by USAID Contract
AIDta c-ll00
iv
TABLE OF CONTENTS
ChaptePage
rIST OF - TABLES vii
IST OF FIGURES bull bull A 66 viii
IST OF SYMBOLS- bull X
1 INTRODUCTION bull 1
Purpose 2
Scope bull 2
II DEVELOPMENT OF WEIR AND ORIFICE EQUATIONS 3
General Features 3
Basic Equations for Weirs and Orifices 3
Weir Performance--Submerged
Orifice Equation 4
Weir Equation 7
III DERIVATION OF CIRCULAR WEIR EQUATION 12
Derivation 12
IV SUBMERGED WEIR FLOW ANALYSIS 22
V EXPERIMENT FACILITIES AND GATE GEOMETRIES 29
VI RESULTS AND DISCUSSIONS 36
Results 36
Dimensional Analysis 36 Weir Performance--Free Flow 38
Flow 40 Orifice Performance 45
Discussions 49
Head Measurement 49 The Effect of Submergence Ratio 51 The Discharge Coefficient for
the Inclined Submerged Weir 52
ACKNOWLEDGMENTS
The author wishes to express his sincere thanks-tohis
adviser Dr William Hart for the time anduidance he put t into this work The contributionsf Dr Everett Richardson
and) Dr Wynn Walker are also apprecd6ated
Specia thanksare due tothe-authors wife Chi-Mei
who didthe job oftyping the final manuscript and encouraged
the author-al-l thetime
ThiUsi work was supported by fundsfrom the United States
Agency for International Development under Contract No
AIDcsd-24601 Optimum Utilization of Water Resources for
Agriculture with Special Emphasis on Water Removal and
Delivery Systems and Relevant Institutional Development
Partial support was also provided by USAID Contract
AIDta-c-ll00
iv
LIST OF TABLES
Table Page
1 Values of PL(H1 D) = 11228 (H1D)2
- 2884 (H1D3 462 (H1D)
4
- 8 (HID)5 21
2 Dimensions of Test Gates All Variables Refer to Fig 53 35
3 Discharge Equations for Models Investigated 58
4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m 61
5 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Weir Flow 63
6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Heightof 014 m Orifice Flow 67
7 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Weir Flow 71
8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow 73
9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Weir Flow 75
10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Orifice Flow 77
vii
LIST OF FIGURES
F ePage
21 ree Orifice
6 22 SubmergedJet Orifice
Front View of Flow over a Recta~ngular Weir 823
24 ShrCrested -Weir8
1331 Circular Weir
Curve of Function PL(H1D) = 11228 (H D)2
32 3 - (HID)4 168-2884 (HID) 462 bull 20(H1lD)s
41 Submerged Weir 23
Three Types of Weir Flow (After Vennard) bull bull 2742
51 Plan View of Experimental Facilities 30
52 Illustration of Crest Height for Inclindd 33Gate
34 53 Configurations of Gates
61 Free Flow Discharge Coefficient Cdf for
Circular Gates As a Function of Ratio of Upstream Head to Crest Height H1P
= 0090 - 0080 (HIP) CorrelationCidf Coefficient r =0973 39
Submerged Weir Flow Discharge Coefficient62 Cds for Rectangular Gate with a Crest
Height of 008 m As a Function of 1 - S32 S is the Submergence Ratio
Cds= 2069 (1 - $32)0393 Correlation
42=0987 Coefficient r
Submerged Weir Flow Discharge Coefficient63 Cds for 038 m Diameter Circular Gate with
a Crest Height of 014 m As a Function of
1 - s2 S is the Submergence Ratio
= 1128 ( 2 S2)0385 Correlation
Coefficient = 0990 43
viii
LIST OF FIGURES (Continued)
Figure Page
64 Submerged Weir Flow Discharge Coefficient Cds for 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of
1 - S2 S is the Submergence Ratio Cds = 1062 (1 - $2)0 378 Correlation
Coefficient r2 = 0997 44
65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with
a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio
2)0 3 92ds 1210 (1 - Correlation 2Coefficient r = 0993 46
66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H (H1 - H2 ) Q = 136 H0477
Correlation Coefficient r2 = 0992 47
67 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head
Difference H (H1 - H2 ) Q = 133 H0477
2Correlation Coefficient r = 0989 48
68 Submerged Orifice Flow Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of Head
Difference H (H1 - H2 ) Q = 213 H0475
Correlation Coefficient r2 = 0990 50
ix
ISTOF SYMBOLS
Symbol Definition
A Area of flow at weir notch or orifice L2
A0 Areamp-of flowat vena contracta L2k
B Width of channel L
C Cauchy number-
Cc ontraction coefficient
Cd )ischarge coefficient
Cdf )ischarge coefficient for free flow condition
Cds )ischarge coefficient for submerged flow condition
Cv lelocity coefficient
D Diameter of circular weir L
F Froude number 2
g Acceleration due to gravity LTshy
h Head on an elementary area L
H Head difference H1 - H2 L
H1 Upstream head L
H2 Downstream head L
K Coefficient of submerged weir flow discharge coefficient-see Eq 4-4
L Length of rectangular weir notch L
LI Effective length of contracted weir L
m Exponent of submerged weir flow discharge coefficient see Eq 4-4
n Exponent of weir equations
N Number of end contractions
P Crest height L 1
Q Actual total discharge L3Tshy
V
L13T OF SYMBOLS (Continued)
Symbol Definition
Q1 Ideal total discharge L3T1
Qf Free flow discharge L3T I
Qs Submerged flow discharge L3T 1
r Correlation coefficient
R Radius of circular weir L
Re Reynolds number
S Submergence ratio H2H 1 1Velocity of approach LT-
Va Mean velocity in the channel of approach above the crest level LT I
Vb Mean velocity in the channel of approach below the crest level LT-
Vt Theoretical velocity at weir notch or orificeT-1
W Weber number
Y1 Upstream water depth L
Y2 Downstream water depth L
Coefficient corrects for inequality of velocity in the approach channel
- 2 y Specific weight ML-2T
FE Elastic molulus ML-IT- 2
p Density of mass ML
Surface tension MT 2
a 1
Dynamic viscosity ML-1 Tshy
r Gamma function
xi
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
ABSTRACT OF THESIS
DISCHARGE THROUGH INCLINED GATES
Fourga1tes one rectangular andthree circular
installed at 45degreesfto the channelbottomAwere investishy
gated The rectangular gate performedtasa-submerged weir
fonly The-circular gates performed as submergedWeirs-when
the upstream water depth was belowtheltop of-the-circular
opening and performed as orifices When the upstream water
depth wasabove the topof the circular opening -Two-kinds
ofnappes surface nappe and plunging nappewereobserved
in the submerged weir flow conditions Weirdischarges under
plunging nappe flow were independent of downstreamwater
depth so these data were used to calibratethe free flow
discharge equations The free flow discharge-coefficient
for the rectangular gate was constant and for the circular
gates was a function of the ratio of upstream head to the
crest height Data for the surface nappe condition were
used to calibrate the submerged flow discharge equations
The submerged flow discharge coefficients for all gates were
functions of submergence ratio and opening configurations
and different by multiplicative constant from reported
coefficient for vertical sharp-crested weirs The discharge
equations for orifice flow were functions of opening configshy
urations
Chia-Shyun Chen Agricultural Engineering DepartmentColorado State University Fort Collins Colorado 80523 Spring 1977
iii
ACKNOWLEDGMENTS
The author wishes to express his sincere thanks to his
adviser Dr William Hart for the time and guidance he put
intothiswork The contributions of-DrEverettrRichardson
and Dr Wynn Walker-are-also appreciated
1 Chi-MeiSpecial thanksilearedue toi the authors wife
who didthe job oftyping the final manuscript1iand encouraged
theauthor all the time
-iThis iwork wassupportedbyfunds from the United States
Agency for International Developm~entunderContract No
AIDcsd-2460 OptimumUtilizatin of WaterResources for
Agriculture with SpeciaLEmphasis on Water Removal and
PDelivery SYStems and Relevant Institutional Development
partia support was also prvvided by USAID Contract
AIDta c-ll00
iv
TABLE OF CONTENTS
ChaptePage
rIST OF - TABLES vii
IST OF FIGURES bull bull A 66 viii
IST OF SYMBOLS- bull X
1 INTRODUCTION bull 1
Purpose 2
Scope bull 2
II DEVELOPMENT OF WEIR AND ORIFICE EQUATIONS 3
General Features 3
Basic Equations for Weirs and Orifices 3
Weir Performance--Submerged
Orifice Equation 4
Weir Equation 7
III DERIVATION OF CIRCULAR WEIR EQUATION 12
Derivation 12
IV SUBMERGED WEIR FLOW ANALYSIS 22
V EXPERIMENT FACILITIES AND GATE GEOMETRIES 29
VI RESULTS AND DISCUSSIONS 36
Results 36
Dimensional Analysis 36 Weir Performance--Free Flow 38
Flow 40 Orifice Performance 45
Discussions 49
Head Measurement 49 The Effect of Submergence Ratio 51 The Discharge Coefficient for
the Inclined Submerged Weir 52
ACKNOWLEDGMENTS
The author wishes to express his sincere thanks-tohis
adviser Dr William Hart for the time anduidance he put t into this work The contributionsf Dr Everett Richardson
and) Dr Wynn Walker are also apprecd6ated
Specia thanksare due tothe-authors wife Chi-Mei
who didthe job oftyping the final manuscript and encouraged
the author-al-l thetime
ThiUsi work was supported by fundsfrom the United States
Agency for International Development under Contract No
AIDcsd-24601 Optimum Utilization of Water Resources for
Agriculture with Special Emphasis on Water Removal and
Delivery Systems and Relevant Institutional Development
Partial support was also provided by USAID Contract
AIDta-c-ll00
iv
LIST OF TABLES
Table Page
1 Values of PL(H1 D) = 11228 (H1D)2
- 2884 (H1D3 462 (H1D)
4
- 8 (HID)5 21
2 Dimensions of Test Gates All Variables Refer to Fig 53 35
3 Discharge Equations for Models Investigated 58
4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m 61
5 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Weir Flow 63
6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Heightof 014 m Orifice Flow 67
7 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Weir Flow 71
8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow 73
9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Weir Flow 75
10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Orifice Flow 77
vii
LIST OF FIGURES
F ePage
21 ree Orifice
6 22 SubmergedJet Orifice
Front View of Flow over a Recta~ngular Weir 823
24 ShrCrested -Weir8
1331 Circular Weir
Curve of Function PL(H1D) = 11228 (H D)2
32 3 - (HID)4 168-2884 (HID) 462 bull 20(H1lD)s
41 Submerged Weir 23
Three Types of Weir Flow (After Vennard) bull bull 2742
51 Plan View of Experimental Facilities 30
52 Illustration of Crest Height for Inclindd 33Gate
34 53 Configurations of Gates
61 Free Flow Discharge Coefficient Cdf for
Circular Gates As a Function of Ratio of Upstream Head to Crest Height H1P
= 0090 - 0080 (HIP) CorrelationCidf Coefficient r =0973 39
Submerged Weir Flow Discharge Coefficient62 Cds for Rectangular Gate with a Crest
Height of 008 m As a Function of 1 - S32 S is the Submergence Ratio
Cds= 2069 (1 - $32)0393 Correlation
42=0987 Coefficient r
Submerged Weir Flow Discharge Coefficient63 Cds for 038 m Diameter Circular Gate with
a Crest Height of 014 m As a Function of
1 - s2 S is the Submergence Ratio
= 1128 ( 2 S2)0385 Correlation
Coefficient = 0990 43
viii
LIST OF FIGURES (Continued)
Figure Page
64 Submerged Weir Flow Discharge Coefficient Cds for 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of
1 - S2 S is the Submergence Ratio Cds = 1062 (1 - $2)0 378 Correlation
Coefficient r2 = 0997 44
65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with
a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio
2)0 3 92ds 1210 (1 - Correlation 2Coefficient r = 0993 46
66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H (H1 - H2 ) Q = 136 H0477
Correlation Coefficient r2 = 0992 47
67 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head
Difference H (H1 - H2 ) Q = 133 H0477
2Correlation Coefficient r = 0989 48
68 Submerged Orifice Flow Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of Head
Difference H (H1 - H2 ) Q = 213 H0475
Correlation Coefficient r2 = 0990 50
ix
ISTOF SYMBOLS
Symbol Definition
A Area of flow at weir notch or orifice L2
A0 Areamp-of flowat vena contracta L2k
B Width of channel L
C Cauchy number-
Cc ontraction coefficient
Cd )ischarge coefficient
Cdf )ischarge coefficient for free flow condition
Cds )ischarge coefficient for submerged flow condition
Cv lelocity coefficient
D Diameter of circular weir L
F Froude number 2
g Acceleration due to gravity LTshy
h Head on an elementary area L
H Head difference H1 - H2 L
H1 Upstream head L
H2 Downstream head L
K Coefficient of submerged weir flow discharge coefficient-see Eq 4-4
L Length of rectangular weir notch L
LI Effective length of contracted weir L
m Exponent of submerged weir flow discharge coefficient see Eq 4-4
n Exponent of weir equations
N Number of end contractions
P Crest height L 1
Q Actual total discharge L3Tshy
V
L13T OF SYMBOLS (Continued)
Symbol Definition
Q1 Ideal total discharge L3T1
Qf Free flow discharge L3T I
Qs Submerged flow discharge L3T 1
r Correlation coefficient
R Radius of circular weir L
Re Reynolds number
S Submergence ratio H2H 1 1Velocity of approach LT-
Va Mean velocity in the channel of approach above the crest level LT I
Vb Mean velocity in the channel of approach below the crest level LT-
Vt Theoretical velocity at weir notch or orificeT-1
W Weber number
Y1 Upstream water depth L
Y2 Downstream water depth L
Coefficient corrects for inequality of velocity in the approach channel
- 2 y Specific weight ML-2T
FE Elastic molulus ML-IT- 2
p Density of mass ML
Surface tension MT 2
a 1
Dynamic viscosity ML-1 Tshy
r Gamma function
xi
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
ACKNOWLEDGMENTS
The author wishes to express his sincere thanks to his
adviser Dr William Hart for the time and guidance he put
intothiswork The contributions of-DrEverettrRichardson
and Dr Wynn Walker-are-also appreciated
1 Chi-MeiSpecial thanksilearedue toi the authors wife
who didthe job oftyping the final manuscript1iand encouraged
theauthor all the time
-iThis iwork wassupportedbyfunds from the United States
Agency for International Developm~entunderContract No
AIDcsd-2460 OptimumUtilizatin of WaterResources for
Agriculture with SpeciaLEmphasis on Water Removal and
PDelivery SYStems and Relevant Institutional Development
partia support was also prvvided by USAID Contract
AIDta c-ll00
iv
TABLE OF CONTENTS
ChaptePage
rIST OF - TABLES vii
IST OF FIGURES bull bull A 66 viii
IST OF SYMBOLS- bull X
1 INTRODUCTION bull 1
Purpose 2
Scope bull 2
II DEVELOPMENT OF WEIR AND ORIFICE EQUATIONS 3
General Features 3
Basic Equations for Weirs and Orifices 3
Weir Performance--Submerged
Orifice Equation 4
Weir Equation 7
III DERIVATION OF CIRCULAR WEIR EQUATION 12
Derivation 12
IV SUBMERGED WEIR FLOW ANALYSIS 22
V EXPERIMENT FACILITIES AND GATE GEOMETRIES 29
VI RESULTS AND DISCUSSIONS 36
Results 36
Dimensional Analysis 36 Weir Performance--Free Flow 38
Flow 40 Orifice Performance 45
Discussions 49
Head Measurement 49 The Effect of Submergence Ratio 51 The Discharge Coefficient for
the Inclined Submerged Weir 52
ACKNOWLEDGMENTS
The author wishes to express his sincere thanks-tohis
adviser Dr William Hart for the time anduidance he put t into this work The contributionsf Dr Everett Richardson
and) Dr Wynn Walker are also apprecd6ated
Specia thanksare due tothe-authors wife Chi-Mei
who didthe job oftyping the final manuscript and encouraged
the author-al-l thetime
ThiUsi work was supported by fundsfrom the United States
Agency for International Development under Contract No
AIDcsd-24601 Optimum Utilization of Water Resources for
Agriculture with Special Emphasis on Water Removal and
Delivery Systems and Relevant Institutional Development
Partial support was also provided by USAID Contract
AIDta-c-ll00
iv
LIST OF TABLES
Table Page
1 Values of PL(H1 D) = 11228 (H1D)2
- 2884 (H1D3 462 (H1D)
4
- 8 (HID)5 21
2 Dimensions of Test Gates All Variables Refer to Fig 53 35
3 Discharge Equations for Models Investigated 58
4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m 61
5 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Weir Flow 63
6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Heightof 014 m Orifice Flow 67
7 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Weir Flow 71
8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow 73
9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Weir Flow 75
10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Orifice Flow 77
vii
LIST OF FIGURES
F ePage
21 ree Orifice
6 22 SubmergedJet Orifice
Front View of Flow over a Recta~ngular Weir 823
24 ShrCrested -Weir8
1331 Circular Weir
Curve of Function PL(H1D) = 11228 (H D)2
32 3 - (HID)4 168-2884 (HID) 462 bull 20(H1lD)s
41 Submerged Weir 23
Three Types of Weir Flow (After Vennard) bull bull 2742
51 Plan View of Experimental Facilities 30
52 Illustration of Crest Height for Inclindd 33Gate
34 53 Configurations of Gates
61 Free Flow Discharge Coefficient Cdf for
Circular Gates As a Function of Ratio of Upstream Head to Crest Height H1P
= 0090 - 0080 (HIP) CorrelationCidf Coefficient r =0973 39
Submerged Weir Flow Discharge Coefficient62 Cds for Rectangular Gate with a Crest
Height of 008 m As a Function of 1 - S32 S is the Submergence Ratio
Cds= 2069 (1 - $32)0393 Correlation
42=0987 Coefficient r
Submerged Weir Flow Discharge Coefficient63 Cds for 038 m Diameter Circular Gate with
a Crest Height of 014 m As a Function of
1 - s2 S is the Submergence Ratio
= 1128 ( 2 S2)0385 Correlation
Coefficient = 0990 43
viii
LIST OF FIGURES (Continued)
Figure Page
64 Submerged Weir Flow Discharge Coefficient Cds for 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of
1 - S2 S is the Submergence Ratio Cds = 1062 (1 - $2)0 378 Correlation
Coefficient r2 = 0997 44
65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with
a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio
2)0 3 92ds 1210 (1 - Correlation 2Coefficient r = 0993 46
66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H (H1 - H2 ) Q = 136 H0477
Correlation Coefficient r2 = 0992 47
67 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head
Difference H (H1 - H2 ) Q = 133 H0477
2Correlation Coefficient r = 0989 48
68 Submerged Orifice Flow Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of Head
Difference H (H1 - H2 ) Q = 213 H0475
Correlation Coefficient r2 = 0990 50
ix
ISTOF SYMBOLS
Symbol Definition
A Area of flow at weir notch or orifice L2
A0 Areamp-of flowat vena contracta L2k
B Width of channel L
C Cauchy number-
Cc ontraction coefficient
Cd )ischarge coefficient
Cdf )ischarge coefficient for free flow condition
Cds )ischarge coefficient for submerged flow condition
Cv lelocity coefficient
D Diameter of circular weir L
F Froude number 2
g Acceleration due to gravity LTshy
h Head on an elementary area L
H Head difference H1 - H2 L
H1 Upstream head L
H2 Downstream head L
K Coefficient of submerged weir flow discharge coefficient-see Eq 4-4
L Length of rectangular weir notch L
LI Effective length of contracted weir L
m Exponent of submerged weir flow discharge coefficient see Eq 4-4
n Exponent of weir equations
N Number of end contractions
P Crest height L 1
Q Actual total discharge L3Tshy
V
L13T OF SYMBOLS (Continued)
Symbol Definition
Q1 Ideal total discharge L3T1
Qf Free flow discharge L3T I
Qs Submerged flow discharge L3T 1
r Correlation coefficient
R Radius of circular weir L
Re Reynolds number
S Submergence ratio H2H 1 1Velocity of approach LT-
Va Mean velocity in the channel of approach above the crest level LT I
Vb Mean velocity in the channel of approach below the crest level LT-
Vt Theoretical velocity at weir notch or orificeT-1
W Weber number
Y1 Upstream water depth L
Y2 Downstream water depth L
Coefficient corrects for inequality of velocity in the approach channel
- 2 y Specific weight ML-2T
FE Elastic molulus ML-IT- 2
p Density of mass ML
Surface tension MT 2
a 1
Dynamic viscosity ML-1 Tshy
r Gamma function
xi
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
TABLE OF CONTENTS
ChaptePage
rIST OF - TABLES vii
IST OF FIGURES bull bull A 66 viii
IST OF SYMBOLS- bull X
1 INTRODUCTION bull 1
Purpose 2
Scope bull 2
II DEVELOPMENT OF WEIR AND ORIFICE EQUATIONS 3
General Features 3
Basic Equations for Weirs and Orifices 3
Weir Performance--Submerged
Orifice Equation 4
Weir Equation 7
III DERIVATION OF CIRCULAR WEIR EQUATION 12
Derivation 12
IV SUBMERGED WEIR FLOW ANALYSIS 22
V EXPERIMENT FACILITIES AND GATE GEOMETRIES 29
VI RESULTS AND DISCUSSIONS 36
Results 36
Dimensional Analysis 36 Weir Performance--Free Flow 38
Flow 40 Orifice Performance 45
Discussions 49
Head Measurement 49 The Effect of Submergence Ratio 51 The Discharge Coefficient for
the Inclined Submerged Weir 52
ACKNOWLEDGMENTS
The author wishes to express his sincere thanks-tohis
adviser Dr William Hart for the time anduidance he put t into this work The contributionsf Dr Everett Richardson
and) Dr Wynn Walker are also apprecd6ated
Specia thanksare due tothe-authors wife Chi-Mei
who didthe job oftyping the final manuscript and encouraged
the author-al-l thetime
ThiUsi work was supported by fundsfrom the United States
Agency for International Development under Contract No
AIDcsd-24601 Optimum Utilization of Water Resources for
Agriculture with Special Emphasis on Water Removal and
Delivery Systems and Relevant Institutional Development
Partial support was also provided by USAID Contract
AIDta-c-ll00
iv
LIST OF TABLES
Table Page
1 Values of PL(H1 D) = 11228 (H1D)2
- 2884 (H1D3 462 (H1D)
4
- 8 (HID)5 21
2 Dimensions of Test Gates All Variables Refer to Fig 53 35
3 Discharge Equations for Models Investigated 58
4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m 61
5 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Weir Flow 63
6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Heightof 014 m Orifice Flow 67
7 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Weir Flow 71
8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow 73
9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Weir Flow 75
10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Orifice Flow 77
vii
LIST OF FIGURES
F ePage
21 ree Orifice
6 22 SubmergedJet Orifice
Front View of Flow over a Recta~ngular Weir 823
24 ShrCrested -Weir8
1331 Circular Weir
Curve of Function PL(H1D) = 11228 (H D)2
32 3 - (HID)4 168-2884 (HID) 462 bull 20(H1lD)s
41 Submerged Weir 23
Three Types of Weir Flow (After Vennard) bull bull 2742
51 Plan View of Experimental Facilities 30
52 Illustration of Crest Height for Inclindd 33Gate
34 53 Configurations of Gates
61 Free Flow Discharge Coefficient Cdf for
Circular Gates As a Function of Ratio of Upstream Head to Crest Height H1P
= 0090 - 0080 (HIP) CorrelationCidf Coefficient r =0973 39
Submerged Weir Flow Discharge Coefficient62 Cds for Rectangular Gate with a Crest
Height of 008 m As a Function of 1 - S32 S is the Submergence Ratio
Cds= 2069 (1 - $32)0393 Correlation
42=0987 Coefficient r
Submerged Weir Flow Discharge Coefficient63 Cds for 038 m Diameter Circular Gate with
a Crest Height of 014 m As a Function of
1 - s2 S is the Submergence Ratio
= 1128 ( 2 S2)0385 Correlation
Coefficient = 0990 43
viii
LIST OF FIGURES (Continued)
Figure Page
64 Submerged Weir Flow Discharge Coefficient Cds for 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of
1 - S2 S is the Submergence Ratio Cds = 1062 (1 - $2)0 378 Correlation
Coefficient r2 = 0997 44
65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with
a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio
2)0 3 92ds 1210 (1 - Correlation 2Coefficient r = 0993 46
66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H (H1 - H2 ) Q = 136 H0477
Correlation Coefficient r2 = 0992 47
67 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head
Difference H (H1 - H2 ) Q = 133 H0477
2Correlation Coefficient r = 0989 48
68 Submerged Orifice Flow Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of Head
Difference H (H1 - H2 ) Q = 213 H0475
Correlation Coefficient r2 = 0990 50
ix
ISTOF SYMBOLS
Symbol Definition
A Area of flow at weir notch or orifice L2
A0 Areamp-of flowat vena contracta L2k
B Width of channel L
C Cauchy number-
Cc ontraction coefficient
Cd )ischarge coefficient
Cdf )ischarge coefficient for free flow condition
Cds )ischarge coefficient for submerged flow condition
Cv lelocity coefficient
D Diameter of circular weir L
F Froude number 2
g Acceleration due to gravity LTshy
h Head on an elementary area L
H Head difference H1 - H2 L
H1 Upstream head L
H2 Downstream head L
K Coefficient of submerged weir flow discharge coefficient-see Eq 4-4
L Length of rectangular weir notch L
LI Effective length of contracted weir L
m Exponent of submerged weir flow discharge coefficient see Eq 4-4
n Exponent of weir equations
N Number of end contractions
P Crest height L 1
Q Actual total discharge L3Tshy
V
L13T OF SYMBOLS (Continued)
Symbol Definition
Q1 Ideal total discharge L3T1
Qf Free flow discharge L3T I
Qs Submerged flow discharge L3T 1
r Correlation coefficient
R Radius of circular weir L
Re Reynolds number
S Submergence ratio H2H 1 1Velocity of approach LT-
Va Mean velocity in the channel of approach above the crest level LT I
Vb Mean velocity in the channel of approach below the crest level LT-
Vt Theoretical velocity at weir notch or orificeT-1
W Weber number
Y1 Upstream water depth L
Y2 Downstream water depth L
Coefficient corrects for inequality of velocity in the approach channel
- 2 y Specific weight ML-2T
FE Elastic molulus ML-IT- 2
p Density of mass ML
Surface tension MT 2
a 1
Dynamic viscosity ML-1 Tshy
r Gamma function
xi
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
ACKNOWLEDGMENTS
The author wishes to express his sincere thanks-tohis
adviser Dr William Hart for the time anduidance he put t into this work The contributionsf Dr Everett Richardson
and) Dr Wynn Walker are also apprecd6ated
Specia thanksare due tothe-authors wife Chi-Mei
who didthe job oftyping the final manuscript and encouraged
the author-al-l thetime
ThiUsi work was supported by fundsfrom the United States
Agency for International Development under Contract No
AIDcsd-24601 Optimum Utilization of Water Resources for
Agriculture with Special Emphasis on Water Removal and
Delivery Systems and Relevant Institutional Development
Partial support was also provided by USAID Contract
AIDta-c-ll00
iv
LIST OF TABLES
Table Page
1 Values of PL(H1 D) = 11228 (H1D)2
- 2884 (H1D3 462 (H1D)
4
- 8 (HID)5 21
2 Dimensions of Test Gates All Variables Refer to Fig 53 35
3 Discharge Equations for Models Investigated 58
4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m 61
5 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Weir Flow 63
6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Heightof 014 m Orifice Flow 67
7 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Weir Flow 71
8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow 73
9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Weir Flow 75
10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Orifice Flow 77
vii
LIST OF FIGURES
F ePage
21 ree Orifice
6 22 SubmergedJet Orifice
Front View of Flow over a Recta~ngular Weir 823
24 ShrCrested -Weir8
1331 Circular Weir
Curve of Function PL(H1D) = 11228 (H D)2
32 3 - (HID)4 168-2884 (HID) 462 bull 20(H1lD)s
41 Submerged Weir 23
Three Types of Weir Flow (After Vennard) bull bull 2742
51 Plan View of Experimental Facilities 30
52 Illustration of Crest Height for Inclindd 33Gate
34 53 Configurations of Gates
61 Free Flow Discharge Coefficient Cdf for
Circular Gates As a Function of Ratio of Upstream Head to Crest Height H1P
= 0090 - 0080 (HIP) CorrelationCidf Coefficient r =0973 39
Submerged Weir Flow Discharge Coefficient62 Cds for Rectangular Gate with a Crest
Height of 008 m As a Function of 1 - S32 S is the Submergence Ratio
Cds= 2069 (1 - $32)0393 Correlation
42=0987 Coefficient r
Submerged Weir Flow Discharge Coefficient63 Cds for 038 m Diameter Circular Gate with
a Crest Height of 014 m As a Function of
1 - s2 S is the Submergence Ratio
= 1128 ( 2 S2)0385 Correlation
Coefficient = 0990 43
viii
LIST OF FIGURES (Continued)
Figure Page
64 Submerged Weir Flow Discharge Coefficient Cds for 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of
1 - S2 S is the Submergence Ratio Cds = 1062 (1 - $2)0 378 Correlation
Coefficient r2 = 0997 44
65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with
a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio
2)0 3 92ds 1210 (1 - Correlation 2Coefficient r = 0993 46
66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H (H1 - H2 ) Q = 136 H0477
Correlation Coefficient r2 = 0992 47
67 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head
Difference H (H1 - H2 ) Q = 133 H0477
2Correlation Coefficient r = 0989 48
68 Submerged Orifice Flow Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of Head
Difference H (H1 - H2 ) Q = 213 H0475
Correlation Coefficient r2 = 0990 50
ix
ISTOF SYMBOLS
Symbol Definition
A Area of flow at weir notch or orifice L2
A0 Areamp-of flowat vena contracta L2k
B Width of channel L
C Cauchy number-
Cc ontraction coefficient
Cd )ischarge coefficient
Cdf )ischarge coefficient for free flow condition
Cds )ischarge coefficient for submerged flow condition
Cv lelocity coefficient
D Diameter of circular weir L
F Froude number 2
g Acceleration due to gravity LTshy
h Head on an elementary area L
H Head difference H1 - H2 L
H1 Upstream head L
H2 Downstream head L
K Coefficient of submerged weir flow discharge coefficient-see Eq 4-4
L Length of rectangular weir notch L
LI Effective length of contracted weir L
m Exponent of submerged weir flow discharge coefficient see Eq 4-4
n Exponent of weir equations
N Number of end contractions
P Crest height L 1
Q Actual total discharge L3Tshy
V
L13T OF SYMBOLS (Continued)
Symbol Definition
Q1 Ideal total discharge L3T1
Qf Free flow discharge L3T I
Qs Submerged flow discharge L3T 1
r Correlation coefficient
R Radius of circular weir L
Re Reynolds number
S Submergence ratio H2H 1 1Velocity of approach LT-
Va Mean velocity in the channel of approach above the crest level LT I
Vb Mean velocity in the channel of approach below the crest level LT-
Vt Theoretical velocity at weir notch or orificeT-1
W Weber number
Y1 Upstream water depth L
Y2 Downstream water depth L
Coefficient corrects for inequality of velocity in the approach channel
- 2 y Specific weight ML-2T
FE Elastic molulus ML-IT- 2
p Density of mass ML
Surface tension MT 2
a 1
Dynamic viscosity ML-1 Tshy
r Gamma function
xi
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
LIST OF TABLES
Table Page
1 Values of PL(H1 D) = 11228 (H1D)2
- 2884 (H1D3 462 (H1D)
4
- 8 (HID)5 21
2 Dimensions of Test Gates All Variables Refer to Fig 53 35
3 Discharge Equations for Models Investigated 58
4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m 61
5 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Weir Flow 63
6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Heightof 014 m Orifice Flow 67
7 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Weir Flow 71
8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow 73
9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Weir Flow 75
10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 018 m Orifice Flow 77
vii
LIST OF FIGURES
F ePage
21 ree Orifice
6 22 SubmergedJet Orifice
Front View of Flow over a Recta~ngular Weir 823
24 ShrCrested -Weir8
1331 Circular Weir
Curve of Function PL(H1D) = 11228 (H D)2
32 3 - (HID)4 168-2884 (HID) 462 bull 20(H1lD)s
41 Submerged Weir 23
Three Types of Weir Flow (After Vennard) bull bull 2742
51 Plan View of Experimental Facilities 30
52 Illustration of Crest Height for Inclindd 33Gate
34 53 Configurations of Gates
61 Free Flow Discharge Coefficient Cdf for
Circular Gates As a Function of Ratio of Upstream Head to Crest Height H1P
= 0090 - 0080 (HIP) CorrelationCidf Coefficient r =0973 39
Submerged Weir Flow Discharge Coefficient62 Cds for Rectangular Gate with a Crest
Height of 008 m As a Function of 1 - S32 S is the Submergence Ratio
Cds= 2069 (1 - $32)0393 Correlation
42=0987 Coefficient r
Submerged Weir Flow Discharge Coefficient63 Cds for 038 m Diameter Circular Gate with
a Crest Height of 014 m As a Function of
1 - s2 S is the Submergence Ratio
= 1128 ( 2 S2)0385 Correlation
Coefficient = 0990 43
viii
LIST OF FIGURES (Continued)
Figure Page
64 Submerged Weir Flow Discharge Coefficient Cds for 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of
1 - S2 S is the Submergence Ratio Cds = 1062 (1 - $2)0 378 Correlation
Coefficient r2 = 0997 44
65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with
a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio
2)0 3 92ds 1210 (1 - Correlation 2Coefficient r = 0993 46
66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H (H1 - H2 ) Q = 136 H0477
Correlation Coefficient r2 = 0992 47
67 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head
Difference H (H1 - H2 ) Q = 133 H0477
2Correlation Coefficient r = 0989 48
68 Submerged Orifice Flow Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of Head
Difference H (H1 - H2 ) Q = 213 H0475
Correlation Coefficient r2 = 0990 50
ix
ISTOF SYMBOLS
Symbol Definition
A Area of flow at weir notch or orifice L2
A0 Areamp-of flowat vena contracta L2k
B Width of channel L
C Cauchy number-
Cc ontraction coefficient
Cd )ischarge coefficient
Cdf )ischarge coefficient for free flow condition
Cds )ischarge coefficient for submerged flow condition
Cv lelocity coefficient
D Diameter of circular weir L
F Froude number 2
g Acceleration due to gravity LTshy
h Head on an elementary area L
H Head difference H1 - H2 L
H1 Upstream head L
H2 Downstream head L
K Coefficient of submerged weir flow discharge coefficient-see Eq 4-4
L Length of rectangular weir notch L
LI Effective length of contracted weir L
m Exponent of submerged weir flow discharge coefficient see Eq 4-4
n Exponent of weir equations
N Number of end contractions
P Crest height L 1
Q Actual total discharge L3Tshy
V
L13T OF SYMBOLS (Continued)
Symbol Definition
Q1 Ideal total discharge L3T1
Qf Free flow discharge L3T I
Qs Submerged flow discharge L3T 1
r Correlation coefficient
R Radius of circular weir L
Re Reynolds number
S Submergence ratio H2H 1 1Velocity of approach LT-
Va Mean velocity in the channel of approach above the crest level LT I
Vb Mean velocity in the channel of approach below the crest level LT-
Vt Theoretical velocity at weir notch or orificeT-1
W Weber number
Y1 Upstream water depth L
Y2 Downstream water depth L
Coefficient corrects for inequality of velocity in the approach channel
- 2 y Specific weight ML-2T
FE Elastic molulus ML-IT- 2
p Density of mass ML
Surface tension MT 2
a 1
Dynamic viscosity ML-1 Tshy
r Gamma function
xi
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
LIST OF FIGURES
F ePage
21 ree Orifice
6 22 SubmergedJet Orifice
Front View of Flow over a Recta~ngular Weir 823
24 ShrCrested -Weir8
1331 Circular Weir
Curve of Function PL(H1D) = 11228 (H D)2
32 3 - (HID)4 168-2884 (HID) 462 bull 20(H1lD)s
41 Submerged Weir 23
Three Types of Weir Flow (After Vennard) bull bull 2742
51 Plan View of Experimental Facilities 30
52 Illustration of Crest Height for Inclindd 33Gate
34 53 Configurations of Gates
61 Free Flow Discharge Coefficient Cdf for
Circular Gates As a Function of Ratio of Upstream Head to Crest Height H1P
= 0090 - 0080 (HIP) CorrelationCidf Coefficient r =0973 39
Submerged Weir Flow Discharge Coefficient62 Cds for Rectangular Gate with a Crest
Height of 008 m As a Function of 1 - S32 S is the Submergence Ratio
Cds= 2069 (1 - $32)0393 Correlation
42=0987 Coefficient r
Submerged Weir Flow Discharge Coefficient63 Cds for 038 m Diameter Circular Gate with
a Crest Height of 014 m As a Function of
1 - s2 S is the Submergence Ratio
= 1128 ( 2 S2)0385 Correlation
Coefficient = 0990 43
viii
LIST OF FIGURES (Continued)
Figure Page
64 Submerged Weir Flow Discharge Coefficient Cds for 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of
1 - S2 S is the Submergence Ratio Cds = 1062 (1 - $2)0 378 Correlation
Coefficient r2 = 0997 44
65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with
a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio
2)0 3 92ds 1210 (1 - Correlation 2Coefficient r = 0993 46
66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H (H1 - H2 ) Q = 136 H0477
Correlation Coefficient r2 = 0992 47
67 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head
Difference H (H1 - H2 ) Q = 133 H0477
2Correlation Coefficient r = 0989 48
68 Submerged Orifice Flow Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of Head
Difference H (H1 - H2 ) Q = 213 H0475
Correlation Coefficient r2 = 0990 50
ix
ISTOF SYMBOLS
Symbol Definition
A Area of flow at weir notch or orifice L2
A0 Areamp-of flowat vena contracta L2k
B Width of channel L
C Cauchy number-
Cc ontraction coefficient
Cd )ischarge coefficient
Cdf )ischarge coefficient for free flow condition
Cds )ischarge coefficient for submerged flow condition
Cv lelocity coefficient
D Diameter of circular weir L
F Froude number 2
g Acceleration due to gravity LTshy
h Head on an elementary area L
H Head difference H1 - H2 L
H1 Upstream head L
H2 Downstream head L
K Coefficient of submerged weir flow discharge coefficient-see Eq 4-4
L Length of rectangular weir notch L
LI Effective length of contracted weir L
m Exponent of submerged weir flow discharge coefficient see Eq 4-4
n Exponent of weir equations
N Number of end contractions
P Crest height L 1
Q Actual total discharge L3Tshy
V
L13T OF SYMBOLS (Continued)
Symbol Definition
Q1 Ideal total discharge L3T1
Qf Free flow discharge L3T I
Qs Submerged flow discharge L3T 1
r Correlation coefficient
R Radius of circular weir L
Re Reynolds number
S Submergence ratio H2H 1 1Velocity of approach LT-
Va Mean velocity in the channel of approach above the crest level LT I
Vb Mean velocity in the channel of approach below the crest level LT-
Vt Theoretical velocity at weir notch or orificeT-1
W Weber number
Y1 Upstream water depth L
Y2 Downstream water depth L
Coefficient corrects for inequality of velocity in the approach channel
- 2 y Specific weight ML-2T
FE Elastic molulus ML-IT- 2
p Density of mass ML
Surface tension MT 2
a 1
Dynamic viscosity ML-1 Tshy
r Gamma function
xi
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
LIST OF FIGURES (Continued)
Figure Page
64 Submerged Weir Flow Discharge Coefficient Cds for 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of
1 - S2 S is the Submergence Ratio Cds = 1062 (1 - $2)0 378 Correlation
Coefficient r2 = 0997 44
65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with
a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio
2)0 3 92ds 1210 (1 - Correlation 2Coefficient r = 0993 46
66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H (H1 - H2 ) Q = 136 H0477
Correlation Coefficient r2 = 0992 47
67 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head
Difference H (H1 - H2 ) Q = 133 H0477
2Correlation Coefficient r = 0989 48
68 Submerged Orifice Flow Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of Head
Difference H (H1 - H2 ) Q = 213 H0475
Correlation Coefficient r2 = 0990 50
ix
ISTOF SYMBOLS
Symbol Definition
A Area of flow at weir notch or orifice L2
A0 Areamp-of flowat vena contracta L2k
B Width of channel L
C Cauchy number-
Cc ontraction coefficient
Cd )ischarge coefficient
Cdf )ischarge coefficient for free flow condition
Cds )ischarge coefficient for submerged flow condition
Cv lelocity coefficient
D Diameter of circular weir L
F Froude number 2
g Acceleration due to gravity LTshy
h Head on an elementary area L
H Head difference H1 - H2 L
H1 Upstream head L
H2 Downstream head L
K Coefficient of submerged weir flow discharge coefficient-see Eq 4-4
L Length of rectangular weir notch L
LI Effective length of contracted weir L
m Exponent of submerged weir flow discharge coefficient see Eq 4-4
n Exponent of weir equations
N Number of end contractions
P Crest height L 1
Q Actual total discharge L3Tshy
V
L13T OF SYMBOLS (Continued)
Symbol Definition
Q1 Ideal total discharge L3T1
Qf Free flow discharge L3T I
Qs Submerged flow discharge L3T 1
r Correlation coefficient
R Radius of circular weir L
Re Reynolds number
S Submergence ratio H2H 1 1Velocity of approach LT-
Va Mean velocity in the channel of approach above the crest level LT I
Vb Mean velocity in the channel of approach below the crest level LT-
Vt Theoretical velocity at weir notch or orificeT-1
W Weber number
Y1 Upstream water depth L
Y2 Downstream water depth L
Coefficient corrects for inequality of velocity in the approach channel
- 2 y Specific weight ML-2T
FE Elastic molulus ML-IT- 2
p Density of mass ML
Surface tension MT 2
a 1
Dynamic viscosity ML-1 Tshy
r Gamma function
xi
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
ISTOF SYMBOLS
Symbol Definition
A Area of flow at weir notch or orifice L2
A0 Areamp-of flowat vena contracta L2k
B Width of channel L
C Cauchy number-
Cc ontraction coefficient
Cd )ischarge coefficient
Cdf )ischarge coefficient for free flow condition
Cds )ischarge coefficient for submerged flow condition
Cv lelocity coefficient
D Diameter of circular weir L
F Froude number 2
g Acceleration due to gravity LTshy
h Head on an elementary area L
H Head difference H1 - H2 L
H1 Upstream head L
H2 Downstream head L
K Coefficient of submerged weir flow discharge coefficient-see Eq 4-4
L Length of rectangular weir notch L
LI Effective length of contracted weir L
m Exponent of submerged weir flow discharge coefficient see Eq 4-4
n Exponent of weir equations
N Number of end contractions
P Crest height L 1
Q Actual total discharge L3Tshy
V
L13T OF SYMBOLS (Continued)
Symbol Definition
Q1 Ideal total discharge L3T1
Qf Free flow discharge L3T I
Qs Submerged flow discharge L3T 1
r Correlation coefficient
R Radius of circular weir L
Re Reynolds number
S Submergence ratio H2H 1 1Velocity of approach LT-
Va Mean velocity in the channel of approach above the crest level LT I
Vb Mean velocity in the channel of approach below the crest level LT-
Vt Theoretical velocity at weir notch or orificeT-1
W Weber number
Y1 Upstream water depth L
Y2 Downstream water depth L
Coefficient corrects for inequality of velocity in the approach channel
- 2 y Specific weight ML-2T
FE Elastic molulus ML-IT- 2
p Density of mass ML
Surface tension MT 2
a 1
Dynamic viscosity ML-1 Tshy
r Gamma function
xi
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
V
L13T OF SYMBOLS (Continued)
Symbol Definition
Q1 Ideal total discharge L3T1
Qf Free flow discharge L3T I
Qs Submerged flow discharge L3T 1
r Correlation coefficient
R Radius of circular weir L
Re Reynolds number
S Submergence ratio H2H 1 1Velocity of approach LT-
Va Mean velocity in the channel of approach above the crest level LT I
Vb Mean velocity in the channel of approach below the crest level LT-
Vt Theoretical velocity at weir notch or orificeT-1
W Weber number
Y1 Upstream water depth L
Y2 Downstream water depth L
Coefficient corrects for inequality of velocity in the approach channel
- 2 y Specific weight ML-2T
FE Elastic molulus ML-IT- 2
p Density of mass ML
Surface tension MT 2
a 1
Dynamic viscosity ML-1 Tshy
r Gamma function
xi
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
CHAPTER I
INTRODUCTION
It has been demonstrated that losses along water
courses (channels which receive water from the distributory
and discharge that water into individual farmers fields or
into branch water courses) are a primary cause of low overall
irrigation efficiencies in less developed countries (LDC)
A particular need in overcoming these low efficiencies is
effective control and measurement structures Proper control
structures allow diversion of water to where it is needed
and measurement structures provide the data necessary to
evaluate overall irrigation efficiencies
Two types of gates which can be used as both control
and measurement structures and which are adaptable for use
in LDCs have been designed in Pakistan by the Colorado
State University Water Management Research Group (i) Both
are designed to fit into a channel or channel constriction
of rectangular section One has a rectangular opening and
the other a circular opening Both are installed at a 45
degree inclination to the horizontal so that gravity will
assist in holding the gate in place and in sealing it against
leakage In both cases a compressible sponge rod is used
as the sealing material The gate frames and gate closure
panels are cast of reinforced concrete
Numbers in parentheses refer to similarly numbered items in the Literature Cited
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
PURPOSE The purpose of hecurrent investigation is-to determine
the diScharge equations of the gates mentioned above
SCOPE
Fourgates werei used in this -study threeof-which have
-a- cir6ularopening the fourth of Which had a rectangular opening The rectangular gate had a0a46mwide opening and
O1 llm high crest For ithe circular gates two opening-a
-diameters were studied 038 mand -046m The 0 46i
diameter gatehad acrest height of 1020m The other two
circular gates had the same diameter opening 0V3 8 but
different crest heights 016 m-and i-022 Im
--The-hydraulic data were collected under-both0 free flow
Land submerged flow conditions The medthod 6f subMerged flowU
analysib reported by Villemonte- (2) was utilized-iif developshy
ing tie ratingcurves for those ates operatingunder subshy
(merged flow conditions Theseratings were then compared
with thosebtainedfor vertical weirs (2) in -oiderto
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
APTER jII
DEVELOPMENT OWEIR AND ORIFICE EQUATIONS
GENERALFEATURES
By means of the law of energy conservation nearly any
kind of a contraction to flow in a closed conduit or an open
channel can be employed as a metering device In this study
the two types of gates were used as discharge metering
devices The rectangular one performed asasubmeredweir
with partial contraction The circular one performed as an
orifice when the water surface upstream from the gate was
above the top of the opening It performed as a submerged
weir when the upstream water surface drops below the top of
the opening
Generally weirs are classified (3) as head-area meters
They apply only to open conduits and involve a simultaneous
variation of head and area which means that the area of the
fluid flowing through the weir notch is a function of the
upstream head Orifices can be used either in closed conduits
or in open conduits In both cases the cross-sectional area
of the fluid flowing through the opening is cohstant and
hence they are classified as head meters
BASIC EQUATIONS FORWEIRS AND ORIFICES It wasshown byMavis (4) that orifices and Ii simple
exponential-shape weirs bear a single-family reiationship of
the form
=C AHi (2-1)
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
4
where Qf = free-flowidischarge C =a discharge coefficient
A arke6 ii ampIfl0in gthrbughthdt-Ottdh S = head on
the crest
As stated above the area A in Eq 2-1 is a constant
when in orifice flow and A is a function of H1 when
weir flow octurs The specific equations for orifices and
weirs are now discussed
ORIFICE EQUATION
The velocity of a fluid approaching an orifice or
similar device is called the velocity of approach In
Fig 21 it is assumed that the plan area of the tank is so
large relative to that of the orifice that the velocity at
point (1) is negligible If the Bernoulli equation is
written between points (1) and (2) and it is recognized
that the pressures at both Doints are eaual to atmosnheric
pressure then
whereeV 2t is the theoretical velocity because no friction
loss is cinsidered H1 is the head on the orifice and g
is the acceleration of gravity Owing to friction the
actual average velocityV2 at point (2) is less than the
theoretical velocity V2t and the ratio V2V2 t = Cv is
called the-velocity coefficient Thus V2 =CvV2t The
actual discharge is
AoV2 t = (CcA) (C V2--l) =C)CvA 2j1-l (2-2)
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
5
where Cc the contraction coefficient is the ratio of
the area Adeg at the vena contracta to the area of the
orifice A bull The discharge0qoefficient C is introduced
as
C= CcCv
Therefore Eq 2-2 can be written as
Q = CdAyg- 1 (2-3)
Equation 2-3 is the discharge equation for a free jet orifice
Figure 22 shows a submerged jet orifice With the
notation of Fig 22 realizing that the pressure head in the
vena contracta at point (2) is equal to y the Bernoulli
equation results in
H + y = y + V2t22g
and therefore
V2t = gf
where H is the difference between the upstream and downstream
head (Fig 22) According to the definitions just given
the actual discharqe is
Q = CdA2gH (2-4)
Equation 2-4 is the discharge equation for a submerged jet
orifice
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
Watd~erEsurface
H1
CL of orif ce
Fig 21 Free Jet Orifice
Water surface
H
Water surface
CL of orifice y
rig SubmergedJetOrifice
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
7
WEIR EQUATION
In 1716 Poleni studied a rectangular sharp-crested
weir withoutend contractions (Fig 23) 4nd assumed that
the velocity over the vertical section at the crest must
vary with the square root of the distance below the level
of the approaching _flow To derive a flow equation for the
weir consider An elementary area dA= Ldh and the
velocity through this area is assumed to be 7-i The
total flow through the total area is
H1 Q = Cd f V7-E Ldh = 23 Cd 7g L H132 (2-5)
where h is the head on an elemental area Ldh is theH1 head measured from the top of the crest to the undisturbed
water surface (Fig 24) and other symbols are as defined
previously This type of weir with the sides of the
channel acting as the ends of the weir has no end contracshy
tions of the nappe and is called a suppressed weir
If the effect of approach velocity is included the
discharge equation is (5)
v2 32 Wv2 32(26 a -Q = CL[(H 1 + ) (c )3] (2-6)
where C = 23 2g Cd of Eq 2-5 a = correction coefficient
for inequality of velocities in the channel of approach
V22g= velocity head due to the mean velocity of approach
V and H = measured head as defined for Eq 2-5
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
Water surface
Crest-
L
ig23 Front View of Flow over a Rectangular Weir
Water surface
H1 --C-- -- r e s
0
p
Fig-24 Sharp-Crested Weir
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
9
If the sides of the notch have sharp upstream edges so
that the nappe is contracted in width the weir is said to
have end contractions and is called a contracted weir End
contractions reduce the effective length of a weir Francis
(5) in 1852 found that
L = L - 01 NH1 (2-7)
where L = effective length of weir L = measured length
N = number of end contractions For two complete end conshy
tractions N = 2 and if the contraction is suppressed at
one end only N = 1 The measured head H1 is defined
in Eq 2-5 As a result the Francis formula for a weir with
both ends contracted neglecting the velocity of approach (6)
is
Q = 333 H132 (L - 02 H1) (2-8)
If the velocity of approach is included
V2 32 v2 32 Q = 333 [(H1 + - 2g ](L - 02 H1 )
(2-9)
where all symbold are as previously defined
Some additional important formulas for rectangular weirs
are listed below (5) Those formulas are all written in the
form for suppressed weirs If there are end contractions
length L is represented with the effective length L of
Eq 2-7 All formulas given here are in English units
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
10
Th Fteley and Sterns formula (1883)
Q = 331 L (HI +15 + 0007 L
rhe Bazin formula (1888)
23 Yg L H3H32 (060 01476 )(0675 + H
H 2
(1 + 055 ) Y1 2
where Y1 is the upstream water depth measured from the
channel invert
The Frese formula (1890)
H 3223 7g L (0615 + 000689 x - 1 2 HI2
2H(1 + 055 ) 1
Y12
The Rehbock formula (1912)
3 2 1 + 008H1= 23 2g L H1 ( 0605 + 320H 1 3 P
where P is the height of crest
The King formula (1918) 12
Q = 334 L HII 4 7 (1 + 056 2 ) Y1
-rne twiss Society of Engineers and Architects formula
HI -(0L3 0615
1 (0615 + 305H 1 + 1 6)x
(1+ 05 ) Y1
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
The Schoder formula (1927)
Q = 333 L [(H + -+ )32 + V-2 1 shy
where V is the mean velocity in the channel of approach
a above the crest level and Vb is the mean velocity in the
channel of approach below the crest level
As discussed above the velocity of approach and end
contractions do have effects on the discharge However in
this study the simplest rectangular weir equation 2Q = Cd L V H1 3 (2-10)
is applied which means that the effects of the velocity of
approach and end contractions are included in the discharge
coefficient Cd
As for the circular weir equation there are no availshy
able formulas which can be used to compute the data collected
for the circular gates The derivation of the circular weir
equation is by no means as simple as that for a rectangular
weir and is given in detail in Chapter III The submerged
weir condition is discussed in Chapter IV
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
CHAPTERIII
DERIVATION OF CIRCULAR WEIR EOUATION
In this chapter the circular weir equation is derived
Two well-known mathematical relations are used here The
first of these is the binomial expansion
(i-X) = l-NX + N(N-I) X2 N(N-I) (N-2) X3
21 3
+ N(N-)(N-2f)(N-3) X4 +4-1
which is convergent for the case X2 lt 1 In these studies
n = 12 and the expansion becomes
x2= 1x- x-2 1 3 5
7 5 (3 -1) 23 X obull
The second needed relationship is a definite integral
a 1a+n+l N )r (=) 1n2f jP (a2-X2) dX = T am+n+3 (3-2) r )30
0 2
where m n are any real positive numbers and r(w) is
the gamma function of w
DERIVATION
With the notations of Fig 31 assume that the ideal
vlcoity of a stream filament issuing from a weir notch at
a distance h below the undisturbed water surface is g
The area of this filament dA is 2Xdh and hence the
ideal discharge Q through the total area is
12
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
13
D -
R-H1
- TF-HI R
x
Fig 31 Circular Weir
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
14
H1 l Q V5E Xdh
n
Introducing the discharge coefficient Cd as defined
previously the actual total discharge
H1 Q 2C 7 f X V dh
0
Q becomes
(3-3)
where
2 1 2(R2 + h)- (3-4)X (R -H
and R is the radius of the opening
Expanding Eq 3-4
2 1 2SX= [2R(H - h) - (H1 - h)I
is the diameter ofReplacing -R--with -D2 where D
the opening yields
X = [D(H - h) -(H - h)2]11 2 (3-5)
Combining Eq 3-3 and 3-5 the discharge becomes
H1 Q = 2Cd f F VVD(H1 h) - (H1 - h)2 dh
0
(3-6)
Let
u - h +uH1
Then
du =-dh
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
15
and
IL= when h = H
Equation 3-6 becomes
Q 2CdH f U u- - u2(-du) H
Q4 2Cd I VH1 - u VDu - u2du (3-7)
Inoder to apply the binomial expansion the first
axpression under the integral is written
M1 u= 1 V1 uH1
This meets the criterion of X2lt 1 because 0 lt u lt H1
2and so (UHl) lt 1 Thus
1 u 2 1 331
lu-~-i (l)4~ ~ T~~F 1 1
58 u - (3-8)
12 1
By siilarmanipulation the second expression under
the integral becomes
1 u2 _ u 3 bullg-=) - ]2 (1-SD1-2- VD lshy
5 u4 -(3-9)
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
16
Tthe expression under the integral now becomes
1H - Uu =u 1
HD
A 2 2 3
H1 H1
12 HH
234 23 3F 3 7 5 5 +2-- 3 DH 755Q5 c d 31 55
N~~~~~~~I (D- L
H H H H 25 42 5
Q22-3 D[~ 2 L2+J3TWher iegat by ter abesult ioncomntem Eq 3-7 - H H H 2 1 21 H11 H2 1
1 1
3 ~2
Tnere is a domnon term H1 2 in the above equation it
canbe thus~~~~ in- nfnt eredqitennthe variable
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
17
H
d 1 DH
- 0033 (H) - 0012 H1 3 - ] (3-10)
One can now write
ri Q = Cd V2gD H 2PL () (3-11)
where
HI I H1
PL (H-) = [0802 - 0206 (H1 -) 0033 (H)2D D-- D
- 0012 (--) 3]
H1 The polynomial function PL (-) is a convergent infinite
D series of which the value cannot be exactly determined However aspecial case can indicate the error between the infinite series and the polynomial function with finite terms The special case is that when H = R or when the weir is half full Equation 3-3 can then be integrated by means of the definite integral Eq 3-2 In this case
x = 2 -=h2
so that Eq 3-3 becomes
R SQ-2Cd TR 2 --- 2- dh (3-12)
0
Comparingq 3-12 with Ea -2 i4- a--nt that m 12 n = 1 and the following results
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
18
1+1 1+2
or
R5 2Q=CdV-2 49 2(3-13)r(1
The values of the three gamma functions can be obtained from
mathematical table (7) and Eq 3-13 becomes
R 5 2Q= 09585 Cd2 (3-14)
On the other hand Eq 3-11 the general equation for a
circular weir under the special case of flowing half full
is as follows
= d 22R R2 PL (2)
or
R5 2 Q =Cd - r2 PL (1) d 2
Thusj
Q= 09747 Cd22 Ru amp (3-15)
Comparing the coefficients in Eqs 3-14 and 3-15 it is
seen that the difference is 00162 which is about 17
perceAt The finite polynomial PL (H1D) for the special
-Waseinvestigated thus compares closely with the exact
solution of the same case The error would be even less if
nnrA fralR warampUed in the determination of PL (H D) In
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
19
the calculations given here Eqs 3-8 and 3-9 were only
expanded to the 8th degree
X Equation 3-11 can be rewritten bynoting that
2ro 2 D5 H D Hence
C D5 2 PL (-s) (3-16)
where
HL(-g (1)2 PL (_PLI()
H 1)
11228 () 2 - 2884 ( -)3 462 H 4
H1
168 (H 5
and here g = 29800 mmsec
The curve of the above function PL(H1D) is plotted
on Fig 32 In addition its values between HID = 01
to H1D = 089 with an increment of 001 are shown in Table 1
Equation 3-16 is the discharge equation of a circular
weir with diameter D neglecting the approach velocity
Because the end contractions in a circular weir cannot be
properly defined this circular weir equation does not
However their effectiveexplicitly include their effects
is included in the discharge coefficient Cd
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
20
50
S I I
40
N30
20
10 D D 00 01 02 03 04 05 06 07 08
H D
-ig 12 Curte of Function PL(H1 D) 11228 HL 2 D)
281A4(-l) 3 2(--)4 - 168 (-l5shy
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
2 3 _4 5
Table 1 Values of PL(HID) = 11228(H1 D) 2 2884(HID) - 462H1 D) - 168(HID)
000 001 002 003 004 005 006 007 008 009
01 109 132 157 183 212 243 275 310 346 385
02 425 467 512 557 605 655 706 759 814 -870
03 929 988 1050 1113 1178 1244 1312 1381 1452 1524
04 1598 1674 1750 1828 1908 1989 2071 2154 2239 2325
05 2412 2501 2590 2681 2773 2866 2960 3055 3-151 3248
06 3346 3445 3545 3646 3747 3850 3953 4057 4162 4267
07 4373 4480 4587 4695 4804 4913 5023 3133 5243 5354
08 5465 5577 5688 5801 5913 6025 6138 6251 6364 6477
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
CHAPTER IW
SUBMERGED WEIR FLOW ANALYSIS
A submerged weir freguently-proves t be a useful and-economicalM6t -i open
eleterng deviceinopen channels where headcan
not be sacrificed But in using a weir the difficulties are
to accurate1y predict the effects of submergence and to
select the weir formula which is most iikely to give reliable
results Becauseweirflow teither free or submerged is
a gravity phenomenon in which-friction plays little part
dynamic similarity is governed by the Froudelaw The
dimensionless ratios H2H1 and PH (Fig 41) are also
important
In 143 Vennard and Weston (8) compared the data of
five hydraullic workers -- Francis Fteley Bazin Cox and
Cone -- and made graphs to show the-possible relationships for
submerged-flow through-vertical weirs ennard and Weston
plotted the discharge ratio QQf (tht ratio of the actual
discharge to free flow discharge) against the submergence
ratio H2H1 for various values of PH1 It was found
that all the data points with a constant value of PH1 fell
on one curveand for different value of PH the curves
changed iThis implied that
Qf PH1)fHHl
Later Villemonte (1) obtained more valuable results by
assuming tfnat the netflow over theweir isthe difference
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
23
H1
H2
H1
P Y2
Fig 41 Submerged Weir
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
24
between the free-flow discharge due to H1 and the freeshy
flow discharge due to H9 Then
Q = -Q2 (4-1)
where Q is the net flow over the weir Q1 is the flow due
to the head H1 and Q2 is the flow due to the head H2
This assumption implies that the head H2 does not directly
affect the flow of water due to H1 and likewise that head
H1 does not prohibit counterflow due to H2 This approach
is equivalent to an application of the principle of supershy
position which is frequently used in evaluating the combined
effect of several independent conditions Dividing through
by Q1 I Eq 4-1 becomes
=QQ1 1 - Q2QI (4-2)
Equation 4-2 should not be espected to give a quantitative
relation for determining 0 since interaction and other
perturbing influences have been entirely neglected The
experimental tests Villemonte did showed that QQ1 was
related functionally to 1 - Q2Q but that the appropriate
function was not the simple linear one of Eq 4-2 This
relation may be expressed in the form
QQ1 = f(l - Q2QI) = K(l - Q2Q1)m (4-3)
or since
01 = C1HI1 and Q = C2H2
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
25
then
=QQ1 K( - C2 H2 2CH1n1) m (4-4)
where K and m are constants and are determined from data and the Cs and ns are the coefficients and exponents
that appear in the free-flow discharge equation (such as
Eq 2-10 or Eq 3-11) For an ideal weir of identical
upstream and downstream conditions the coefficients C1 and C2 and the exponents n1 and n2 should be equal
Then Eq 4-4 reduces to
QQ1 = K(1 - Sn)m (45)
where S = the submergence ratio H2H1 The constant K and the exponent m which account for the interaction
effects were determined separately for each weir type but only the arithmetic average of the Ks and the ms were reported The values given were K equal to 100 and m equal to 0385 for a practical submergence range of 0 to
090 Thus the general discharge equation for all sharpshy
crested weirs expressed by continuous single-valued functions
is
Q = Qf (1 - Sn) 0385 (4-6)
In this study the submerged weir problem is analyzed
by Villemontes method First the free-flow equation is
determined by using the standard weir formulas For the
rectangular gate Eq 2-10 is employed For the circular
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
26
gate Eq 3-11 is used The 45 degree inclination is
neglected at this moment allowing comparison with the
vertical weir data referred to by Villemonte More precisely
the exponents for both circular or rectangularweirs are
assumed to be the-same values as in the standard weir equations
or n = 15 for a rectangular gate and n = 2 for a circular
gate Attention should be paid to the fact that the circular
gate equation employed in the study is Eq 3-11 rather than
the general Eq 3-16 The former was chosen because the
general Eq 3-16 does not show the desired exponent n which
is needed in the submerged weir flow equation It is also
noted that truly free flow for weirs were not obtained in
this experiment as explained in Chapter VI
Figure 42 shows three different possible weir flow types
In Fig 42a true free flow donditions are shown This
indicates that the water level in the downstream channel is
sufficiently below the crest to allow free access of air to
the area beneath the nappe Sometimes an air vent is needed to
assure a free access of air to the area beneath the nappe
-Figure 42b and Figure 42c show the two possible submerged
weir flow conditions the surface nappe and plunging nappe
Iho former occurs at high submergence ratios and the latter
at Jojw submergence ratios The surface nappe remains on the
water surface- all stream paths are directed downstream and
standing wavcas are developed The plunging nappe plunges
beneath he water surface and rises to the surface at a point
doWnstream where some stream paths are directed upstream
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
27
a Free flow
Standing ware HI
H
pi
b Surface nappe
P
c Plunging nappe
Fig 42 Three Types of Weir Flow (After Vennard)
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
28
The transition from surface nappe to plunging nappe can be
identified by a breaking of the standing wave crests similar
This implies thatin apprearance to a hydraulic (jump
critical flow could occurwhen the pilunging nappe is present
Actually critical flow does occur inthe plunging nappe
It iscondition and this will be discussed in Chapter VI
known that when critical flow occurs4n the vicinity of a
contraction in an open channel the downstream water depth has
no effect on the upstream water depth Therefore in the
submerged weir problem plunging nappe flow behaves as free
flow and--data for plunging nappe flow were used to calibrate
the free flow equation
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
CHAPTER V
EXPERIMENTAL FACILITIES AND GATE G9METRIES
The data for this study were collected using a test
channel located in the Hydraulics Laboratory of the
Engineering Research Center at fColorado State -University
Fort Collins Colorado The test channel-1-is i83tm wide
122mdeep and 18 29lm long In this experiment the 183 m
widechannel is dividedby a partition into two subchannels
one with a width of 122 m the other with a width of 061 m
and the gate is installed in the 061 m wide subchannel
(Fig 51) The testchannel has a zero slope The water
is supplied from a sump located-under-the Engineering
Research Center building and is circulated bya propeller
pumpwhich gives a makimum capacity of 156 litersper second
The water is transported from fhe pump to the head of
the test channel by a-030 m diameter pipeline which is
1ocatedalong the bullfloor of the laboratory A i025 m diameter
orifice is set in thetipipelinei andthe dischargeican be
determined from the rating cur e of the orifice
Q = 573 VH
where Q is the discharge in liters per second and H is
the differential headOn the orificelin mm The upstream
and downstream heads are read from manometers attachednear
the upstream and downftreAm aces of the orifice
The watekr is very turbulent when it emerges from the
head sumpm and this could cause large fluctuations in flow
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
sump --122 SHead sumpDownstreamsuImpN m
ate
061 m
025 miorifice
Fig 51 Plan View of Experimenta1 Facilities
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
31
aept- throughout the length of the channel This turbuience is removed by installinga damper atthe entrance ofthe subchannel There isaso a damper insta e a the downshysreamsump of thetest channel to prevenE possible vortex flowor turbulence fromoccurringshy
Asthe stream passes over theweir thetop surface curves downward This drawdownextends upstream from the weir notch The upstream head Hi must be measured at a point on the water surface in the channel at a distance
beyond which any significant drawdown occurs This distance is at least four times the maximum head on the weir (6) Four manometers are placed upstream from the gate at distances of 030 122 244 and 488 m As the water passes through the constriction the contracted stream reaches a minimum width which corresponds to the vena contracta in orifice flow Beyond the vena contracta the live stream expands until it reaches downstream where the water surface is undisturbed The downstream undisturbed water depth is taken as the downshystream head H2 Seven manometers are placed downstream to determine the undisturbed flow range They are located downshystream from the gate at distances of 130 132 137 183 335 488 and 549 m The four upstream manometers are tapped 008 m above the bottom of the channel and the seven downstream manometers are tapped 003 m above the bottom of the channel The water level in the eleven manometers could be read to an accuracy of 254 mm (01 inch) the water level in the manometers of the orifice could be
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
32
readi tw an-accura 0f 1 12 inch The _diac
can bevaried by- adjustingthe valve on theR ipeihe
Thecrest height of the- inclinedo gates-i
ilUxstrated byFi 5 2 The configurationand dikenstonsshy
of the four gates are- illustrated byi Fig 53 and Tablet 2
The-partidulr gga-esinvestigatedwerechosentobe geometshy
Eca-ly-SimiAa-ngatesused inthe field
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
P = 008m0308m o D = 038m P = 014m shy
or D = 038m P = 019
Seal 45 Seal ALA)
pP
Rectangular gate Circular gate
Fig 52 Illustration of Crest Height for Inclined Gate
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
34
A
092 m
Section A-A
S 062 m
Rectangular gate
A
CH SG AA
section A-A HJ
062 m Circular gate
Fig 53 Configurations of Gates
I 192 m
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
Table 2 Dimensions of Test Gates All Variables Refer to Fig 53
RECTANGULAR CIRCULAR CIRCULAR CIRCULAR P = 008 m D = 038 m P = 014 m D = 038 m P = 019 m D = 046 m P = 018 m
A 046 m 048 m 048 m 056 m B 008 m 038 m 038 m 046 m C 005 m 002 m 002 m 002 m D 003 m 003 m 003 m 003 m E 008 m 008 m 008 m 008 m In
F 004 m 004 m 004 m 004 m G 004 m 004 m 004 m 004 m H 010 m 018 m 016 m J 015 m 023 m 021 m
K 007 m 007 m 003 m
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
CHAPTER VI
RESULTS AND DISCUSSION
RESULTS
Since th equations for rectangular and circular weirs
have been determined the main purpose is -to find a dimensionshy
less relation for the discharge coefficient Cd which can
then be applied to an gates with different dimensions so long
as they are geometrically similar For the rectangular gate
weir flow only exists either submerged or free For the
circular gates both the weir flow and orificeflow which
could be submerged or free in each condition should be conshy
sidered Dimehsibnal analysis was employed to help find the
relationship between possible dimensionless factors such as
the submergence ratio S the Froude number F etc and
the dimensionless discharge coefficient Cd
DIMENSIONAL ANALYSIS
In general the important variables that can influence
fluid motion are the-following (1) the several linear dishy
mensions fully defining the geometrical boundary conditions-1
L1 L L3 L4 etc which might be the crest height the
width of the weir notch the width of the approach channel or
the water depth of the flow (2) Kinematic and kynamic charshy
acteristics of flow -- a mean velocity V (or a discharge Q)
and A pressure incrementAp(or a resisting force or an
intensity of shear)rand (3) the fluid properties of density
p 6pecific weighty v iscosity i surface tension a
36
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
37
and elastic modulus - Application of the 11theorem gave
the following relatiOnship between the dischargecoefficient
C and dimensionless parameters (9)
Cd = f(L L2 LI1L3 F e W C)
where L1L2 L1L3 L1L4 are some linear dimension ratiosI4
one of which might be a submergence ratio S H2H F
is the Froude number and F = (V2L1)(yAp) Re is the
Reynolds number and Re = (VL1 )(VAp) W is the Weber
number and W = (V2L1 )(aAp) and C is the Cauchy number
and C = V2(cAp)
In open channel flow friction force plays little part
compared with gravity and hence the Reynolds number Re is
not important Water is considered an imcompressible fluid
and its density does not change appreciably in the test thereshy
fore the Cauchy number C is neglected The Weber number
W is important only when the molecular attraction which
gives rise to the liquid properties of cohesion and adhesion
plays a primary role in a fluid problem The most common case
of such a problem is the capillary rise of liquid in a tube
In an open channel fluid problem the molecular attraction
usually has little influence on the flow In weir studies
cohesive forces would be significant if the nappe tend to
cling to the weir surface This condition did not occur in
these studies and so the Weber number could be eliminated
The Froude number which reflects gravity forces has no
effect on the discharge coefficient over the range of flows
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
38
4 nvesagateanere ihus thei discharge coeff icients ofthe
weirandorificeare functions oflihneardimensionratios
only
MEIR PERFOMANCE -- FREE FLOW
As mentioned before the of a free-flow weir wasCd
calibrated by using the data collected ata plunging nappe
condition For the rectangular weir the free flow discharge
coefficient Cdf was calculated by Eq 2-10 and
32)Cdf =Q(L2 H1
where Q is the observed discharge at the upstream head equal
to H1 bull Similarly Cdf of a circular weir was calculated
by Eq 3-11 and
Cdf = H12pL (D--)
or
)]Cd= Q[D HI2PL(Hl- c 1 =2 H
where PL( -) is the polynomial function derived in Chapter
Iv After several different linear dimension ratio had been
tried it was found that Cdf for the rectangular gate was
constant 0481 but Cdf for the other three circular weirs
had a linear relationship with 1lP (Fig 61) The free
flow equation for the rectangular gate with a crest height of
008 m hence is
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
09
o08
A-- D = 038 m P = 014 m
-- D = 038 m P = 019 m
-- D = 046 m P = 018 m
07 13 15 17 19 21 23 25
HIP
Fig 61 Free Flow Discharge Coefficient Cdf forCircular Gates As a Functionof Ratio of Upstream Head to Crest Height H1 P Cdf = 0090 - 0080 (HIP)
2Correlation Coefficient r = 0973
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
40
32 106(61 Qf = 0481 L2- H1 x(6-1)
where Qf is in liters per second L and H1 are in mm
g equals 900 mmsec2 and Uhenf er 1-6 isthe c6nshy
version factor from cubic millimeters per second to liters per
second The-same dimensions are used throughout this report
The unique relation for the three circular gates between
Cdf and H1P is
Cdf = 0990 - 0080 H1P (6-2)
and hence
PL(H1D) x 10- 6Qf = (0990 - 0080 H1P) D
52
(6-3)
Equation 6-1 is the discharge equation for the rectangular
gate when plunging nappe flow takes place Equation 6-3 is
the discharge equation for the three circular gates provided
a plunging nappe occurs
WEIR PERFORMANCE -- SUBMERGED FLOW
After the discharge equations for free flow were
determined the discharge equations for submerged flow could
be calculated by the method illustrated in Chapter IV
The submerged discharge coefficient Cds is the ratio
of the submerged discharge to the discharge calculated from
the free flow equation using the same head H1 Therefore
for the rectangular gate Cds could be expressed as
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
41
Cds = Q(Cdf L H132) (6-4)
and for circular gates
Cds QQ[CD PL(H D)] (6-5)
In Eq 6-4 and 6-5 Q is the observed value of
discharge and Cdf is that determined previously The
values of Cds then were plotted against the values of
(1 - Sn) on logarithmic paper with Cds as the ordinate and
(1 - Sn) as the abscissa (Figs 62 63 64 and 65)
The symbol S has the same meaning H2H1 as in Chapter
IV The value of n is 32 for rectangular gates and 2 for
circular gates As expected for each single gate a
straight line resulted from plotting the data The equations
for the four straight lines are as follows
For the rectangular gate with a crest height of 008 m
(Fig 62)
3 9 3Cds = 2069 (1 - S3 2 ) 0 (6-6)
For the 038 m diameter gate with a crest height of
014 m (Fig 63)
Cds = 1128 (1 - S2 )0 385 (6-7)
For the 038 m diameter gate with a crest height of
019 m (Fig 64)
3 7 8 Cds = 1062 (1 - S2) 0 (6-8)
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
42
Isc
001 01
Fig 62 Submerged Weir Flow Discharge Coefficient Cds
for Rectangular Gate with a Crest Height of 008 m
As a Functionofi - S 2 S is the Submergence Ratio Cds = 2069 (1 - $32)0393 Corelation
Coefficient r2 -0987
10
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
43
O0
0
0
0 _ - shy0 1 10
2Sshy
3 uDmergea wear Flow Discharge Coefficient C for 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of 1 - s2 S is
S2the Submergence Ratio Cds =1128 (1 - 0385
Correlation Coefficient r2 0990
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
7 F l
1
S2 1 -
Fig 64 Subierged Weir Flow Discharge Coefficient C-
fr 038-MDidined Circulari Gate with a crest HeIghtof 019mAs a Function of - S is the SubmergenceRatio -C =062 (1 - S2) 0378
Correlation Coefficient r2 =O997
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
45
For the 046 m diameter gate with a crest height of
018 m (Fig 65)
O216 (1i- S ) (6-9)
The submerged weir equations could be written as
Qs- C (6-10)
where Cds is as shown in Eqs 6-6 7-6 6-8 and 6-9
Qf is as shown in Eqs 6-1 and 6-3 This completes the weir
equations for free flow and submerged flow
ORIFICE PERFORMANCE
The orifice flow rating curve is developed for the
circular gates when the upstream water depth is above the top
of the circular opening Plotting the discharge Q against
the head difference H between upstream head H1 and
downstream head H2 with Q as the ordinate and H as the
abscissa the data points fall on a straight line when plotted
on log-log paper As a result the discharge equations are
For the 038 m diameter gate with a crest height of
014 m (Fig 66)
Q = 136 H0 4 7 7 (6-11)
For the 038 m diameter gate with a crest height of
019 m (Fig 67)
4 7 (6-12)Q = 133 H0
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
46
10
01 ___
10
1 - S2
Fig 65 Submerged Weir Flow Discharge Coefficient Cds for 046 m Diameter Circular Gate with a Crest Height of 018 m As a Function of 1 - S2 S is the Submergence Ratio Cds = 1210 (1 - $2) 0392
Correlation Coefficient r2 = 0993
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
47
1000
(0U
14 100 shy
101
H (nm)
Fig 66 Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 014 m As a Function of Head Difference H
4 7 7 (H1 - H2 ) Q = 136 H0 Correlation Coefficient 2r = 0992
100
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
_____
1000
In
Ci
101
Fig 67
48
- -H __ _
I0O0
o___lOO__
- 1 - L I I I I I I _ __
110 100
H (nm)
Submerged Orifice Flow Discharge Q for the 038 m Diameter Circular Gate with a Crest Height of 019 m As a Function of Head Difference H
477 (H1 - H2 ) Q = 133 H0 Correlation Coefficient
72 = n-QRq
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
49
For the 046 m diameter gate with a crest height of
018 m (Fig 68)
Q = 213 H (6-13)
In Eqs 6-11 6-12 and 6-13 Q is in liters per
second and H is in mm Equations 6-11 6-12 and 6-13
are the discharge equations for the three circular gates
operated under orifice flow
In this study the values of free flow discharge coshy
efficient Cdf the submerged discharge coefficient Cds
H P and (1 - Sn ) were calculated with the help of a
digital computer The linear regression calculations for all
the rating curves were determined using a Hewlett Packard
programmable calculator
DISCUSSION
HEAD MEASUREMENT - It was observed that the undisturbed
flow took place upstream and downstream at the maximum disshy
charge 156 literssec around the places where the first
manometer and the tenth manometer were set (Fig 51) Thereshy
fore the upstream depth Y1 and the downstream depth Y2
were the values of the water level in the first manometer and
the tenth manometer respectively The maximum depth in the
channel was about 061 m and the discharge of both the
first and the tenth manometer were 488 m from the gate and
hence a general rule to measure Y1 and Y2 was that they
should be measured at a distance at least eight times the
maximum depth of flow The upstream H1 was the value of
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
50
1000 shy
0$4
00shy
ig d Submerged Orifice Flow-Discharge Q for the 046 m Diameter Circular Gate with a Crest Height of
18m As a Function ofHeadDifference H =(H1=- 0 21A 0475 Correlation Coefficient
r2 990= U
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
51
waterdepth measured from thetop df the crest in a weir
flow codiion or
H Y - P
In an orifice flow condition H1 is measued from the
center of the orifice or
H1 =j P --
The quanitity H2 is similarly defined with Y1 replaced
by Y2
THE EFFECT OF SUBMERGENCE RATIO - In a Parshall flume
or a cutthroat flume there is a free flow condition when
critical flow occurs in the vicinity of the flume throat
This critical depth makes it possible to determine the disshy
charge knowing only the upstream depth In this submerged
weir study it was noted that when a surface nappe was
changing into a plunging nappe the standing wave of the
surface nappe appeared very similar to a rolling hydraulic
jump As the discharge increased eventually a hydraulic
jump~wo4Ild take place As critical flow must exist before
a hydraulic jump can occur this observation implies that
critical flow occurs in the vicinity of the weir notch when
a plunging nappe appeared Actually this has been proven
by the free discharge equations (Eqs 6-1 and 6-3) because
only the upstream head H1 was involved in those equations
and they gave a very accurate estimate on the discharge under
the plungingi nappe condition
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
52
The plunging nappecouldoccur only when the submTrgenceZFor4 theeagua
ratio reached some value or below it For therectan ular
gate with a crest height of 008 m the plunging nappe begins
at a submergence ratio of 89 percent at a submergence ratio
of51percent for the 038 m diameter circular gate with a
crest height of 013 m at a submergence ratio of 38 percent
for the 038 m diameter circular gate with a crest height of
019 m and at a submergence ratio of 62 percent for the
046 m diameter circular gate with a crest height of 018 m
One of the distinct differences between submerged weir
flow and submerged jet orifice flow is that a critical flow
can never occur in the vicinity of the orifice opening no
matter how low the submergence ratio This is because the
flow through an prifice follows the law of flow in aclosed
conduit and in a closed conduit critical flow is not defined
This is why only one kind of discharge equation was obtained
in this submerged jet orifice study and in those equations
boththe upstream head and downstream head were involved to
calculate the discharge In addition the submergence ratio
has very little effect on the submerged orifice flow
THE DISCHARGE COEFFICIENT FOR THE INCLINED SUBMERGED
WEIR - The submerged discharge coefficient Cds for weirs
has-the relationship
_Sn)mCds= K(l
As discussed in Chapter IVthe results of Villemontes study
of seven vertical sharp-crested weirs of different shapes when
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
53
averaged arithmieically showedampthat K equa1 to 100 and
mequal-to 0385 the maimiuimvariation of ach from the
average is less than 1 perceht In this study the average
valu of thefour ms 0393 0385 0387 and 0392 is
0387 from which the maximum variation of each is less than
12 percent if the Ks value of each remains the same The
average of the four Ks 2069 1128 1062 and 1210 is
1367 The averaged K results in an average variation of
each is about 20 percent when m = 0387 It is apparent
that the coefficient K is not equal to 100 and varied
considerably with shape For the rectangular gate K = 2069
and for circular gates K is between 1062 and 1210 This
variation from the results of Villemonte was primarily caused
by the inclination of the gates and the unsharped crest The
conclusions reached by comparing the results of this study
with that of Villemontes are
(1) The exponent value m does not vary appreciably
either with shapes or with the inclination of the
weirs and m always approximately equals 0385
(2) The coefficient K equal to 100 for vertical
weirs with all kinds of shapes but K no longer
remains a constant when the gate is installed at
some angle with the channel bottom and K varied
significantly with different shapes
THE DISCHARGE COEFFICIENT FOR THE ORIFICE FLOW -
Reviewing Eqs 6-11 6-12 and 6-13 the discharge equations
for the orifice flow had a constant exponent 0477 It is
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
54
orifice flowthe dispharge _oefficientknownthat for an
onlydepends on theboundary geometry Hencelthearithmetic
ayerage of the two coefficients for the 038 m diameter
circulargates wasitaken and this average value 0843 was
m diameterconsidered the discharge coefficient for the 038
circular gate It had been shown previously that the disshy
charge coefficient was a function of linear dimension ratios
only The same values of Cdmight be used for equal ratios
of the opening diameter to the channel width BL This
resulted in the discharge equation for the orifice flow in
the form
4 77Q = CdA-c H0
and
Cd = 0843 for BL = 0625
Cd = 0925 for BL = 0750
FREE FLOW NEAR THE TOP OF THE OPENING - When the ratio
of upstream head H1 to the diameter D of the circular
opening was greater than about 80 percent to 86 percent
though the submergence ratio was in the plunging nappe flow
range the free flow discharge equation did not give an
accurate flow estimate The error was more than 5 percent
rapidly increasing as the submergence ratio decreased This
problem could be explained as follows
When flow is-at or near the critical state the water
surfaceundulates due to the fact that a minor change in
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
55
specific energy the sum of velocity head and the potential
head will cause a major change in water depth Those minor
specific energy changes may be caused by variations in chanshy
nel roughness cross section slope or deposits of sediment
Therefore the wavy surface associated with critical flow
touches the top of the opening and truly free flow does not occur under such conditions Thus under free flow condishy
tions when the water depth is approaching the top of the opening the free flow discharge equation fails to yield an
accurate answer Knowing this point the restriction of H1D less than 86 percent should be imposed on the applying
of the free flow discharge equation Thus the free flow discharge equation can only be applied when plunging nappe
takes place and H1D is less than 86 percent
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
CHAPTER VII
SUMMARY CONCLUSIONS AND RECOMMENDATIONS
SUMMARYshy
Thepurpose of this -study has been -to developgeneral
lischarge ratings for- thefour gates5 pne rectangular and
threecircular Ashas-been stated earlier the rectangular
late can only operate under weirflow condition The-three
ircular gates canoperate under either weir flow conditions
Then the upstream water depth is lower than the top of-the
ircular opening or orifice flow conditions when- the upshy
tream water depth is higher than the top-of the circular
opening For thelweir flow conditions either free flowor
submerged flow exists For the orifice flow conditions only
submerged type flowtakes place in the studies described here
In this study the discharge is given in liters per
second the weir lengtY L the crest height P the opening
diameter D the upstream head H1 and the downstream head
H2 are all given in mm The acceleration due to gravity
is 9800 mmsce2 H1 and H2 are measured from the top of
the crest to the undisturbed water surface in weir flow conshy
ditions and are measured from the centerline of the circular
opening to the undisturbed water surface in orifice flow conshy
ditions
The results of the investigations are given in Table 3
56
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
57
CONCLUSIONS
(a)H and H2 should be measured at a distance at
least eight times te maximum depth -of flow
(b)The free flbwweir equations Eqs 6-4 And 6-3
sh6uld-be appiied whenH1 D is--Iess then 86
percent
(c)When orifice flowtakes placeboth the upstream head
and downstream heady should be measured and applied to
Eqs 6-11 6-12 and 6-13
RECOMMENDATIONS
Recommendations for further research are
(1)Additional dimensions in crest heights and weir
lengths or opening diameters be studied in order to
determineif there is a general relationship for the
discharge coefficient
(2) More databe observed for circular gates operating
under free flowweir conditions-for HID greater
than 86 percent so that the problem of an undulating
surface touching the top edge of thelopeninq can be
evaluated
(3)Additional inclination angles be studied
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
Table 3 Dischige Equations- for Models investigated
T-ype-- f iFlowDevice_______S
Geometry-weir rge- ow (Sur edljnpe Flow (Plunging Nappe) Submergd Fw rfac Ne)
__________Free =
Rectangular Q C x10 Q =C 1 2 -6
Cdf ds g 3 2 - s 0- 9L = 046 m C df=2069( dsd 0481 Slt 089
77 Sgt089P = 008 m TMP = 18 TMP = TDP = 12TDP = 3 TCP = 65TCP = 15
= 5 x 10 = C D 5 2 pLDCidrcular CPL(HD)
= 0 990 0080HIP = 1128(1 - S 0385Sgt051D = 038 Cdf -l Cds 7
TMP - = 15 TMP = 114
P = 014 m TDP = 0 TDP = 20
TCP = 15 bull TCP = 94 2-0378 m ---099- H P Cd= 1062(1 - S Sgt038038 C 0 9 - df --
57 TI4P =TMP 9 -P = 019 m TDP 0 TDP = 3
54TCP = 9 TCP = 0 13 9 2
D 046 m Cdf 0-080HIP Cds 1210(l 02
) Sgt062
9 TMP = 54TMP = P =018 m TDP = 0 TDP = 4
TCP = 50TCP = 9
Notes TMP = Total Measured Data Points TDP = Total Discarded Data Points TCP = Total Calculated Data Points
OiicsOrifice
_________
6H0477 -TMP = 71 TDP = 26
TCP = 145shy-- 0-U477Q 133Hs-
TMP= 60 TDP 9
TCP = 51 04
Q 2 13H TMP = -39
TDP 2 TCP 371-]
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
59
LITERATURE CITED
1 Hart W E TDY Assignment in Pakistan June 18 -August 2 1975 Final Report Agricultural EngineeringDepartment Colorado State University Fort Collins (Unpublished)
2 Villemonte J R Submerged-Weir Discharge StudiesEngineering News-Record Vol 139 December 1947 pp 866-69
3 ASME Research Committee on Fluid Meters Classificationand Nomenclature Fluid Meters Their Theory and Applishycation 5th ed The American Society of Mechanical Engineers New York 1959 pp 11-13
4 Mavis F T Theres No Mystery in Weir FormulasEngineering News-Record Vol 142 January 1949 p 76
5 King E F Sharp-Crested Weirs Handbook of Hydraulics4th ed McGraw-Hill Co New York 1954 pp 41-14
6 United States Department of the Interior Bureau ofReclamation Weirs Water Measurement Manual 2nd edUnited States Government Printing Office Washington1967 p 20
7 Abramowitz M and Stegun I A eds Gamma Functionand Related Functions Handbook of Mathematical Funcshytions Dover Publications Inc New York 1961 pp 14-18
8 Vennard J K and Weston R F Submergence Effect on Sharp-Crested Weirs Engineering News-Record Vol 130 June 1943 pp 814-16
9 Rouse H Dimensional Analysis Fluid Mechanics forHydraulic Engineers Dover Publications Inc New York1961 pp 14-18
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
60
APPENDIX
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
61
Table 4 Hydraulic Laboratory Data for Rectangular Gate with a Crest Height of 008 m
(Litsec) H
-(rm) H12
(mam) H (mm)
S
64085 258sUl 25192 610 97637 7i37 259b4 25192 762 97064 7131 8454
260bb 2620o
251amp66 25192
a889 1016
96588 96123
9101 264be 25192 1270 95201 9ro 26711 Pb065 1651 93820
10478 2690 25141 1778 93395 7i31 22144 20620 15e24 93118 8469 223vy 20620 1778 92062 8a08 226be 20620 2034 91029 9b72 2303s 20620 2413 89524 4U21 50098
23044 231bu
2Z779 22703
254 457
98897 98026
5606 670
232ul 23541
22677 22703
610 8 38
97382 96439
7080 2369b - 26652 1016 95707 7505 237 b 22677 1118 95303 7Ye30 239u 22652 1270 94sect91 8J483 241b 22703 14a22 94104 8V49 24430 22779 1651 93o242
9ea 2469a4 227979 - 190P5 92282 10J37 249-b 22779 21o84 91250 10932 253-iv 22652 2667 89466
1958 1830$4 1762 -711 9b121 49956 1833 t7572 762 95844 4U71 279sectb 277o57 2929 99183 5b79 281s 21183 330 98825 6d02 281 b 2i757 381 98646 640 282040 27757 4o83 98291 79o22 28391b 27132 584 97937 8O15 2849 2t7732 762 97326 11186 2724 2bI92 2032 92536 11f24 2747lb 25192 2286 91681 12448 2774e 252943 2489 91024 12b17 278bv 25192 2667 90427 14973 141U89
2771b( 27504
19350 19350
84907 8153
6971 70355
1483 2840-94 18969 9525 66572 15i34 11)89
289b 2420U0
11842 15540
10135 8661
659q5 64211
12491 251ye 15794 9398 62694 12f44 258il 1541 10414 59677 12319 25i41 15667 9474 62316
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
62
rlTable A Continued
Q H1 H 2 H S (Litsec) (mm) (mm) (mm)
8038 286i1 27757 864 96983 -7160 379 17 37638 2079 990263 84128 1100
3799 2371o
37638-15845
3 eg567874
04o64 66802
12b96 259b4 19858 6096 76512 13169 2647 19664 6883 74012 16b96 310os4 24176 6858 77901 1679 3154 23922 7620 75842 669 216 3b 26620 1016 99304 7193 2181U 20620 1270 94198 499 254ov7 25192 305 98805 5t79 256-24 2s192 432 98315 3172 1802y 17775 254 98591 4J05 5069
18201 183ub
17597 7572
610 813
96652 95579
1o80 23414 20620 27994 88067 13J10 281uY 25166 3023 89277 14u18 28519 251992 3327 88333 15134 289 b 19147 9830 66076 55o06 2131te 20620 762 96436 34 253i 25192 127 99498
11609 28011 25192 2819 89935 202iY L73-18 2921 85567
410190 23871 20620 3251 86380 8OU36 3807u 3638 432 98866
1i028 247oY 2012 4597 81394 14089 292sub 249938 4267 85389 14i82Vs 49 2951018711b 246841-572 4826ll4 8364693893
6 02 19 0bti 17572 1397 92635 30402 278Bbv 27757 102 99635 3v93 279 sb 7633 152 99455
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
63
Table 5 Hydraulic LaboratoryData for 038 m Diameter Circular Gate with a Crest Height of 014 mWeir Flow
Q H H2 H S (Litsec) (mm) (mm)
3U02 167aab 175ampl18 US TZo 93240 3455 3do2J 4i31
1916 1950b 2-4- V
17264 17264 168a3
L905 2286 3556
90062 88307 82h02
3455 4191 4(015o98 4078
1sect Vb 19804 20j L 2661j 1981
17137 17010 16756 16629 17264
2159 2794 a556 4064 2540
88811 85891 82493 80360 87174
2917 5034 6J44 4YI156 4b31 3138 29017 5J81 5664 6089 6287 -50998 3172 4135 5069 778 7b45 961 94o74 9Y12
104J65 1062O 111000 11638
190 e 100226 2i60j 16883 22344 16629 200 167956 2031w 17010 10677 17264 1908ad 17645 21esde 16502 213ei- 16502 217ov 16248 226 0 162o48 20-1 16883 18616 11264 195 b0 16883 2056 16502 23461 16248 2450j 15740 2564 15359 26= -shy15359 2670i 1497827291 14851 279ji 14597 28440 14343 2920oe 14216
1016 4826 5715
4 0 L4 3302 2413 1397 5080 4826 5461 5842 40e64 1397 2667 4064 72o39 87963 10287
-1079E
11811 12446 13335 14097 -4986
94664 77769 74422 8040 83743 87737 92663 76461 77372 74844 73553 80598 92514 86358 80239 6-178 64236 59888 581i5 55910 54405 52258 50432 48681
UJ976 12b74 13107 5634 5V919 6V38 7)905 7o86 8o81 94089 9V69
29904 303j4b 3 6jj I 9-b- 222-17 23106 24006 24307b 25 1ju P a1 26v
a--62 13835 1J708 10240 15994 15740 15486 152o32 15105 1497 14851
619 6510 8923 Sia7 6223 7366 0309- 9144 0033 1l49 1938
465-9 45592 42008 75730 71989 68120 64 1 62487 60088 57s547 55436
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
64
Table 5 Continued-
H I -shy(Litsee) (ram) (mm)- (mm)
7f31 8100
_8b609
264-Uo 2673w272yf
21328 21328 -21074
50a0 5410
-6223
aD763 79766
-77202 i9147 2789ub 20947 6858 75335 96851o620
2844U294b
20820i 56
76208890
7320669819
1OV88 29837 26312 9525 68076 1155 11V79 12602
3047d 309uo 319Yb
20185 20058 19804
10287 10922 12192
66241 64745 61895
1244 3237 19677 12700 60774 11423 12b46 13197 13650
365sy 3i2 322bu 332abb
19042 18661 18534 180a26
11557 12624 13716 15240
62230 59648 57469 54187
14160 34664 175s18 17145 50537 1444J 353e 17518 17805 49593 14i55 3656d 15740 20828 43042 14S30 380ve 15232 22860 39987 14018 33901 13708 20193 40435 14614 361b 11676 24511 32265 1426 365b6 17264 19304 47210 15e36 3809ve 16883 21209 44321 15f4o 39B70 16502 23368 41389 1035 292bg 20566 86s87 70304 11U73 29964 26439 9525 68211 11666 3089bJ 20185 106968 65423 1216 32124 19931 12192 62045 13439 332obb 19550 13716 58768 13905 3454b 19296 15240 55872 1000 372uj 19042 18161 51184 15e36 383e9b 18534 19863 48269 15633 39616 18280 21336 46142 16171 4164b 18026 236s2 43281 16b8o 4456V I101 27559 38i65 28s32 2286be 22217 635 97o221
_3e57 23190b 22217 889 96152 3b 23 23366 22090 1276 4963 4461 23614 22039 1575 93331 4bs88 238bb 219963 1905 92018 5e0- 1 241041 -M2 -266 e186 0 do533 5664 24504j 21836 26c67 89115 060
44 24842
2170921709
31753429
87241 86369
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
65
Table 5 Continued
Q HI H2 H S (Litsec) -Imi) (m) (im()am)
6Z401- 0 S7192 24SOuJ
84 18280 6223
77-487 74603
8015 10960
2510jb 28440
18026 17264
7112 11176
71708 60703
114015 12064
292od 299
17010 17010
12192 12954
58249 56768
12631 307ib 16683 13843 54946 8469 293e 18026 7366 70990 9u6 264 Ut 17772 863 67297 965710480 2691b
278ub 17518 18915
9398 8890
65083 68027
8439 5640 17899 77e47 69792 9961 265sb 17518 9017 66018 9b84
1OV932 272Y1265-ecf
17264 167FB6
10033118011
63245 5-8655
12149 299b4 16121 13843 53801 12116 307-eb 15740 14986 51226 13i69 3149u 15613 15870 49583 13b65 322sbf 15562 16688 48254 13de54 3174w 15994 15748 50387 12f72 106-63
309bu 2819bb
159994 17010
14986 11176
51626 60349
4158 2184b 19042 2794 87204 13d54 3171id 1602 15240 51987 13b79 327bi 162048 165 10 49600 14i60 344oY 15994 18415 46481 14443 3567r 15740 199939 44115 14160 342a 14978 19304 43690 14928 355be 14851 20701 41772 14Y25 368e 144-70 223952 39297 1335 3271U 1532 17526 46498 2is3i 22907V 22344 635 97237 3483 2323J 22344 889 96173 4i948 23614 22217 1397 94084 4b14 239y 22090 1905 92061 5J52 2437b 21963 2413 90101 5d34 2463u 21836 2794 88656 6457 251u 21709 3480 86185 7080 259o 1582 4318 84328 7s16 2640u 213928 5080 80763 8J26 26991b 21201 5715 78767 8b36 27474 21074 6401 76703 9b72 2831 20020 7493 73535 10139 2881d 20693 8128 71798
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
66
Table 5 Continued
__Q
-(Litisec) H1
~m ) H2
71ii(rm) H (mam) +
S
-Q-03 274 31 144 13208 52i713 11040 89-4 1 470 14478 49906 J20076 13197 -L72
30614 31 4 U 2082U
14343 14216 19804
156o72 172s72 1o6
47786 45147 95120
41o91 214bb 19550 1905 91121 5U913 22690 14296 2794 87352 5806 -3b40
2268b200stib
4i418153
39937- 1905
820771 90502
3Us02 208iu 19804 1016 95120 4021 21ol 1955 1651 92212 5813 218bb 19169 2718 87o582 5721 225yb 18915 3684 83702 6429 234s87 18559 4928 79020 6i25 238bb 185934 5334 77652 7bo90 2464u 18280 6350 74218 6457 2348 186961 4826 79452
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
67
Table 6 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 014 m Orifice Flow
Q H HH2
(LitSec) (n) (mm) 7 (mm)
3877 16906 16094 4695 17364 15840 1524 6514 1838) 15586 2794 10224 163922 97o44 6579 14755 18126 2378 1574P 15434 1937u 1844 17526 1601 20412 1362 19050 16511 21936 1082 20b3 12772 14697 3521 11176 135)9 158o4o 3140 12700 13509 15840 3140 12700 1416u 16983 2759 14224 7080 18634 15459 31e75 7080 18634 15332 3304 7816 19218 15205 4013 7363 19015 15332 3663 8496 19904 15078 4826
10011 21174 14570 6604 11328 22444 14062 832 12761 23714 14554 10b)O141 6L 25492 12792 12700 15655 28159 1203o 16129 7788 19396 15332 4064 7561 19142 15332 3810 56n-7 17745 15840 1905 5664 17999 1584t) 21959 70S0 18888 15459 3Q29 4248 17237 16094 11943 673 17364 1584b 1524 5013 17491 15840 lb1 5834 17872 15713 21-59 6344 181e26 15586 2540 4248 17110 15967 1143
15151 27778 125938 15240 15944 29173 12157 17018 16652 30572 11649 18923 10818 22190 1457u 760 12121 23714 14062 9652 1314u 24984 13427 11557 14047 26254 13046 13208 8354 19904 15332 4572 8836 20285 15205 5080
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
68
Table 6 Continued
Q HI H2 H
(LitSec) (mm) (nMM) (mm
6862 13300 10506 2794 5721 12919 10807 2032 7023 13681 11014 2667 4191 12030 10887 1143 36 82 11776 11014 762
5055 12411 10760 1651 5619 12665 11014 1651
14188 20793 7458 13335 14641 216i82 7204 14478 15972 23841 6061 17780 15576 232s06 6569 16b37 9912 15586 9490 6096
11016 16729 d98e 7747 1132S 172o37 8855 8382 12716 18634 8347 [0287 3682 11776 11141 f35 5007 12284 1C760 1524 5752 12538 10506 2032 623 12919 10506 2413
7080 13427 10252 3175 7624 13808 9998 3U10 8383 14316 9998 4318 4248 11903 10760 1143 6627 140s62 112e68 279
6751 14062 112t8 2794 3747 11776 10887 889
4588 12030 10760 1 7o
9935 16094 9744 6350 11328 17618 9363 8255 1o932 16729 923b 74993 12206 18126 8728 9398 8496 14824 10252 457-2 996u 16221 9871 6350 11328 17618 9236 8382 12744 192o69 8728 10541 4364 7458 64s42 1016 5106 7839 b315 1524
7139 8982 5934 3048 15576 19523 346 19177 16794 26000 5680 2032o 1416o 211a74 79o66 13208
6203C 13681 11268 2413 453) 7458 6188 127C 9960 11328
112b8 13046
5q45 4410
6223 8636
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
69
Table 6 Continued
Q 1 2 H
(LitSec) (mm) (ram) (mm) i
12682 14570 3775 1u795 1416u 16983 2886 14097 75961 9236 5807 3429 7947 8165 8496
9490 9744 9998
5681) 568J 5680
3blO 4064 +316
9969 11268 49-18 6350 7335 8581
9109 9998
5807 5426
3302 4572
9176 10506 5172 5363t 9940 11141 4918 6223 10535 11776 4664 7112 11243 12538 4410 8128 12093 5837
13681 822U
3902 60bJ
9779 2159
6253 8474 6u61 13 6528 8691 593-4 2h67 6751 8728 5934 2794 4248 5664 6287
12157 12792 1838
11014 12887 15894C
114 1905 2540
6967 18888 155hb 33Uc
7618 19142 15459 3683
8071 388t) 3313 4248
19650 17110 168s56 17110
15332 16094 16094 16221
4318 1016 762 889
5296 17745 15967 1778
13395 14330
19523 21047
8093 7585
11430 13402
15378 22698 6950 157+8 16029 23968 64942 17526
1618 141s89 10506 3683 8128 8609
1457i 14951
10252 10252
4316 4699
9091 15332 9998 5334
388C 7204 b315 8b9 6599 8220 5680 2540 9176 10506 5426 5080 77u3 9236 5680 3556 8213 7108
9617 8855
5426 5553
4191 3302
6797 8601 5801 2794 5976 8220 5934 2236
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
70
Table 6 Continued
SHI H2 (Litsec) H1(ram) H2H(mmn) (mrm)
579 7966 6061 1905 6004 8220 5934 2286 6514 84o4 r-0340 20 7080 8855 5807 3048 7080 8601 5553 3048 7591 8982 5426 3556 7958 936 5492b 3810 8383 9490 5299 4191 4701 7204 5934 1270 4956 747 5d83 152 5494 7712 507 1905 6089 79s66 56o8( 22b6 4135 6950 5934 1016 4361 7077 59o34 1143
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
71
Table 7 Hydraulic LaboratoryData for 038m Diameter Circular Gate with a Crest Height of 019 m WeirlFlow
____H H _ _Q 1 2 H S (LitSec) (ram) (mm) (mm)
10-P7kjvI it 706 178465 3047
10 f962 26607 7811 18796 29358 11668 2757 7761 19812 28146 12008 263sb 75a57 20028 26624 5$79 20304 14669 5715 71964 6089 210i 14415 6604 68581 6684 21101 14i87 75m44 65285 7e22 224i 14034 8382 62608 7be73 232bb 1653 9601 58713 8be53 240961 03991 10668 55675 9176 248bb 13272 11582 53400 9t27 256 13018 12624 50770 1077 268bplusmn 1 688 14173 47236 11b26 27801 12510 15367 44877 431 19114 15177 3937 79403 5U13 197 14923 4826 75564
11470 278e 12841 149o86 46145 12J48 288Y 12637 162956 43738 12Y14 2970o 12383 17343 41686 13164 30917 12129 188947 39157 3i80 1841i 15457 2972 83874 4461 18965L 15228 3759 8Q 3 97 1800t 15685 2413 86667 4J05 189bi 15431 3531 81381 5d991 207ov 14695 609 7079 6914 216ob4 14415 7239 660570 763 225Y4 14161 8433 62677 8d969 23811s 165 10160 571315 3b40 2254J 21527 1016 95o493 4078 229i4 21527 1397 93906 4630 232bb 21350 190 91808 5098 235by 21299 2261 90405
14926 353070 17717 17653 50091154o3 370-sie 02909 19411 46t A
9487 254 13145 i292 51882 7euro22 215a7 9827 12700 410068VOZ6 W1tiu 113p67 10414 52109
9j65 222si i13 11176 49860 9486 230bl 108e59 12192 47110
104979 2344e 10732 12700 459802 4b44 169bb 13272 36o83 78278 4599 172jb 131o45 40989 76273 5481 17794 12891 4902 724O 6004 i4Y 12637 5842 68387
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
72
J-TabI ~ ontiud
Q (Lit Se c)
12 (mi -
H(ra ) (mm)
bull4 151077 13933 1245 91800 A13l 13U~8O
l6ub 1~26
137 8o 13526
1965 267
87855 83530
44 18 16701 133049 33i53 79925 U t68 1ZJ19
Z94bu 309ob
19368 191991
10592 1735
64647 62055
L209
1U045 11074
316-u Z53810bOI 24I44 248y
189037 14923
[OE05 10097
1275l 5334
1353 14732
59761 73669 43926 40667
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
73
Table 8 Hydraulic Laboratory Data for 038 m Diameter Circular Gate with a Crest Height of 019 m Orifice Flow
Q
(LitSec) 1
(mm) H2
7(mm)i H (mm)
6174 7149 4736 2413 6655 7454 609 - 45 7193 7861 +559 3302 764b 8165 4355 3blt 7b6 8165 4355 38-10 8071 8546 43955 4191 8468 8877 4178 46v99 8949 9232 i4101 Si31 9412 974u 389d 5842
10025 10451 372o 6731 1062u 11086 34bb 7620 113H5 11975 3u85 Bbo90 11951 12788 2882 9906 12911 14134 2450 116b4 13424 1384b
15023 1576u
26) 1942
12954 13818
3144 1U451 9816 b35 407d 10756 9b689 lU67 4475 5096
10959 11213
9639 94b
13i1 1727
5749 11467 v207 2261 62(12 11798 9308 2489 6655 12128 9181 2946 7U52 12433 9181 3251 7448 12737 9r5 3683 7788 12991 b927 4064 8128 13245 8902 4343 8581 13626 87- 4902 9006 14007 Cb23 5385
10025 15023 8292 b731 10762 15785 7937 7849 11838 17005 7429 9576 1503Z 17411 37 17374 1469b 16928 418 16510 14217 161 39 799 15240 135 14896 1434 13462 1467v 17259 1434 15824 15434 18579 917 17b02 15916 19595 545 19050 16312 20561 291 2 9 11951 12788 2882 9906 12914 13424
14134 15023
2450 2069
11684 12954
13848 157b 1942 13818
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
74
TablJ6 8 Conitinued _____ __ ____1 H2 H
(LitSec (mi) (nu) (mm)
42a40 6 1 033 49s490 41~ 5265494 19+ lb00
6895 4863 20 A2 128 57 181098 7022 11146 285 181 -98 7o022 11176
t135 1460Tu
194068 20865
h3 6o0
130-i8 148o59
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
75
Table 9 Hydraulic Laboratory Data for 048 m Diameter Circular Gate witlia Crest Heighof 018 m Weir Flow
Q H1 H2 fH S (LitlSec) (mm) (mm) (mm)
12036 277 4 3 68857 12602 282i 18967 9322 671048
3197 2887 18840 10033 65251 1345 295aut 1-5-86 10922 62986 146 078 3621r0 18332 11938 600562 154963 310js 18027 13005 58 092 15118 312w 17951 13335 57377 16625 320U 17697 14351 55220 340 252oib 24809 40b 98380 4475 2544 24682 _ 76 97005 5U098 25bb 24682 1016 96046 6332 2607 24479 1600 93864 7450 264 bu Z4377 2083 92128 8196 9176
269b2747
24174 23971
2794 3505
89640 87243
10450 11b46
20tJb - 292OJ
2j-66 23666
4572 5537
83809 81039
12b22 299bb 23539 6426 78554 13U91 3090i 241e58 7823 74749 14698 3i5v1 23031 8560 72904 1566 3250bb 22777 9770 69963 166oL 331-YI _ 105-4i 6241 1692 3357d 22142 11430 65954 17d75 3382b 21888 11938 64708 4oO4 4814
28691y2874b
a38 28111
381 635
98669 97791
5619 290OO 27984 1016 96497
7193 29501 27984 1524 94835 8 13 297ob 27857 1905 93599 91947 302-7 g70172qa 540 91e609
104050 3077u 27476 330a 89272 1132 31ibb 27349 3937 87416 12420 317OV4 27Zs 5Z 85620 12b29 321i7b 27222 4953 84606 13J67 325bb 26968 5588 82836 14926 3331w 24714 660A 80179 15669 3390-b 26460 7493 77931 164s96 345eu 2626 838a 75766 17049 350Vb 26079 9Q17 74308 17388 355o 2552 960I 72995 16171 340Uo 25901 8179 76001 16J97 _17i42
3434 34207
g5895 21634
6 5900 12573
75217 63244
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
76
Q - n2 H S
(LitSec) -(mm) (mn) (mm)
1635 1705 13J056
325obb 329147 2746
17570 173j6
145
14986 1621 17526
53969 52573 37371
13V90 122420
286h 265-1
1C712 20
17907 37430 42322
126040 2727J 1630 16 39277
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985
77
Table 10 Hydraulic Laboratory Data for 048 m Diameter Circular Gate with a Crest Height of 08 m Orifice Flow
Q H____1 -HHI2 2 H
(LitSec) (nun) (ram) (mam)
6372 8526 7510 1016 1222 878u 7510 12s70 7881 90e34 74o59 15s75 8564 9288 7383 1905 92f4 9542 7281 2261 977o 9771 7256 2515 10450 10050 7256 2794 1113u 10304 7129 3175 13735 14542
11523 11955
6748 65e45
47o75 5410
15247 12361 6494 5867 15859 127v93 62965 6528 41ql 52949 4843 406 5463 55(13 474i 7b2 7Ufj9 d524
5935 6367
-7sI 44o67
1219 I880
9657 6748 4411 2337 1079u 72956 4208 3048 115b 7637 4081 3556 1224 d018 3954 40f4 10011 7002 446 2bQ0 1331 8526 3827 4099 14217 9034 37e00 5334 15066 9542 3446 6096 12744 7459 2bo84 4775 11753 6875 2i38 3937 4854 8247 7637 010 579 8399 7561 638 15859 17492 1I1-52 7J41 16284 16652
17797 18229
1152 10152
7645 80977
17020 18534 9672 86bi 11846 10558 7002 3556 12319 10812 7002 3810 12461 10837 7002 3835 124o4 7256 2938 4318 4191 8u43 (o37 4906 15661 9923 34s 6477 16346 10304 3319 6985