Embed Size (px)
Citation preview
PARALLEL JETS EMERGING FROM MULTIPLE GATES: DISTINGUISHING
FLOW CONDITION
By
Mohammad Bijankhan
Salah Kouchakzadeh
Gilles Belaud
5th International Junior Researcher and Engineer Workshop
on Hydraulic Structures
Spa, Belgium, 28-30 August 2014
1
INTRODUCTION
Gates are widely used in irrigation networks in order
to adjust the upstream depth and discharge or to
measure the flow rate.
2
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
“Omidieh” Irrigation network located at the
south part of Iran
INTRODUCTION
For a single gate the classical hydraulic jump can
be used to distinguish the flow condition (Lin et
al. 2002):
3
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
221
1
1 1 8 12
y Fry
INTRODUCTION
4
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
INTRODUCTION
Wide channels
Parallel gates
It is suggested to keep all gates under free flow
condition (Clemmens 2004) 5
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
“Omidieh” Irrigation network located at the
south part of Iran
6
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
Three gates installed in parallel located in Pakistan
7
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
Three radial gates and a weir installel in parallel, Salt
River project (Clemmens 2004)
INTRODUCTION
Practical gats’ configurations:
1. gates with different openings;
2. some gates are in operation and others are
closed.
3. The case for which the gate openings are the
same is less practical (Clemmens 2004).
8
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
Practical gats’ configurations:
1.
2. gates are in operation and others are
3. case for which the gate openings are the
Clemmens 2004).
Practical gats’ configurations:
gates with different
some gates are in operation and others are
closed.
The case for which the gate openings are the
same is less
Practical gats’ configurations:
openings;
gates are in operation and others are
case for which the gate openings are the
Clemmens 2004).
Practical gats’ configurations:
with different openings;
gates are in operation and others are
case for which the gate openings are the
same is less practical (Clemmens 2004).
“SefidRud” Located in the North of Iran
OBJECTIVES
Applicability of the single gate distinguishing
condition to two parallel gates
Interaction between jets
Deriving the distinguishing condition curve for
two parallel gates
9
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
METHODOLOGY
Experimentation
Employing momentum balance
Numerical modeling using OpenFoam (Ongoing
research)
10
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
EXPERIMENTATIONS
University of Tehran
Two gates with different
openings.
11
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
SupAgro, Montpellier
One closed gate;
ADV measurements.
wR/wL=1
wR/wL=1.4
wR/wL=1.88
wR/wL=3.35
Left
Gate
Right
Gate
CLASSICAL HYDRAULIC JUMP LIMITATION
12
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
Left Control Volume
Right Control Volume
Left
gate
Right
gate
Classical Hydraulic Jump
Two jets with different Froude Numbers
Neglecting the interaction between jets
221
1
1 1 8 12
y Fry
Flow
CLASSICAL HYDRAULIC JUMP LIMITATION
13
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
CLASSICAL HYDRAULIC JUMP LIMITATION
14
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
CLASSICAL HYDRAULIC JUMP LIMITATION
15
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
Right Control Volume
Closed
gate
Right
gate
Flow
HYDRAULIC JUMP DUE TO PARALLEL JETS
Hydraulic jump features:
16
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
Right
Gate
Left
Gate
HYDRAULIC JUMP DUE TO PARALLEL JETS
Hydraulic jump features:
(a) Semi classical hydraulic jump
(b) Oblique hydraulic jump
17
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
OBLIQUE HYDRAULIC JUMP
18
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
2.5 1.03
DERIVING THE DISTINGUISHING
CONDITION CURVE
Momentum balance applied between the
supercritical jets and tailwater sections
19
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
2 22 2 2 21, 1, 2
21, 1, 22 2 2
L L L RL R
L R
b y b yQ Q Q BygA gA gA
Control
Volume
Left gate
Right gate
DERIVING THE DISTINGUISHING
CONDITION CURVE
20
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
W
W
Left Gate
Right Gate
W
wR=W(1+) and wL=W(1) 2
R Lw wW
=0 (Single gate)
=1 (One closed gate)
R L
R L
w ww w
RwLw
DERIVING THE DISTINGUISHING
CONDITION CURVE
Neglecting the approach velocity and head loss
energy formula would be:
Neglecting 2 (First order Taylor development),
and 2=1
21
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
1 cy C W
( ) 1 ( ) 0 1 ( )2 ( )L R L R L RQ by g y y
221
1
( ) 1 8 12
y J Fry
2 01
1
2 1yFry
DERIVING THE DISTINGUISHING
CONDITION CURVE
22
2( ) 1 0.29 0.42 0 0.54J
( ) 0.7 1J
DERIVING THE DISTINGUISHING
CONDITION CURVE
23 221
1
( ) 1 8 12
y J Fry
DIFFICULTIES AND FURTHER
DEVELOPMENTS
24
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
Where should be positioned as the tailwater section?
1- A section far downstream the gate
Negligible value of the momentum correction factor
Is it possible to neglect friction forces?
How far it should be?
2- A section just after the jump
Considerable value of the momentum correction factor
Control
Volume
Left gate
Right gate
Control
Volume
Left gate
Right gate
DIFFICULTIES AND FURTHER
DEVELOPMENTS
25
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
The submergence threshold also depends on the
measuring location at the tailwater section
CONCLUSIONS
26
5th
Inte
rnatio
na
l Ju
nio
r Rese
arch
er a
nd
En
gin
eer W
ork
shop
1- Classical hydraulic jump definition can not be
used for the parallel gates;
2- For the parallel jets it is necessary to consider
the jet interactions;
3- Momentum balance can be used to formulate the
submergence threshold;
4- Further studies is modeling the jet interactions
with OpenFoam to find the necessary corrections
and to answer the question about the tailwater
position.
Thank you for your attention
27
5th
Inte
rna
tion
al J
un
ior R
ese
arch
er a
nd
En
gin
eer W
ork
shop
