Submerged flow regimes of PK-Weir - Labyrinth and piano ... 2nd International Workshop on Labyrinth and Piano Key Weirs Paris - Chatou, France 20-22 November 2013 Sommaire I. Introduction

Université Mohamed Khider - BISKRA - ALGERIALaboratoire Aménagements Hydrauliques et Environnement

Tel/Fax : (+213) 033 73 79 62 Mobile : (+213) 062 57 31 24 Email : [email protected]

Paris - Chatou, France 20-22 November 2013

2nd International Workshop on Labyrinth and Piano Key Weirs

Présenté par :- Prof . A.Ouamane

- Mr. F. Belaabed

Submerged flow regimes of PK-Weir

2nd International Workshop on Labyrinth and Piano Key Weirs Paris - Chatou, France 20-22 November 2013

SommaireSommaire

I. Introduction

II. Experimental program

III. Experimental results


1- Effect of the discharge on the submergence of the PK-Weir

2- Comparison of the results obtained on the different models

3- Mathematical relationship of the coefficient of submergence

IV. Conclusion


I. Introduction

The spillway is regarded as one of the most important hydraulic

infrastructures; this returns to its multifunction, it is often used as

component of discharge control and spillway in the rivers. It can be


designed in several forms depending on the characteristics

required, namely, the dimensions and the profile of the cross-section, the

shape of the indentation, the provision in relation to the direction of

flow, and the upstream and downstream conditions of the flow.


Based on these last; there are two types of weirs according to

the conditions of their operation. The first type corresponds to the

free flow weir when water level the downstream does not influence

on the flow to the upstream, as well, the aquifer is assumed to be

free (figure 1-a).


( g )

The second type corresponds to the submerged weir when the

water level downstream affects the water level upstream (figure 1-b).


a- Free flow b- Submerged flow


Figure 1. Definition of hydraulic parameters for the weir under free and submerged flow conditions

� Submerged flow - H*: upstream total head; - h*: upstream piezometric head;- Hd: downstream total head; - hd: downstream piezometric head.

� Free flow- Ho: upstream total head; - ho: upstream piezometric head.


Piezomere Flowmeter 93W2Gate


Figure 2. The experimental facility


�� Model of weirModel of weir


Figure 3. Model of PK-Weir

a- PK-Weir type A2m b- PK-Weir type A1


Table 1. Geometrical characteristics of the experimented model

Model of weir n0 n Lcm

Wcm

W0cmWicm

Bcm

B0cmBicm

BbcmP0=Picm

PK-Weir model APK-Weir model A

A2mA1

1.53

266197

6633

189.5

157

4741

1210.25

1210.25

2320.5

2015


a- Plan view b- Cross section

Figure 4. Geometrical configuration of the model A1

a- Plan view b- Cross section

Figure 5. Geometrical configuration of the model A2m


Wc

� Experimental installations according to the upstream conditions


Wt

Figure 6. PK-Weir with lateral contraction


II Experimental program

Sill


Figure 7. Experimental program

Q 1PK-Weir


a- Phase free flow

hd

h*

h*

hd

III Experimental results


Figure 8 : Different phases of the flow on the PK-Weir

b- Phase transition

c- Phase submerged flow

h*hd


1.5

2

2.5

3

H*/

H0

1- Effect of the discharge on the submergence of the PK-Weir1-1 Effect of the discharge on the submergence of the PK-Weir A2m

a- Phase free flow


Figure 9. Relative upstream head according relative downstream head (model type A2m)

0

0.5

1

-2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3

H

Hd/H0

PK-Weir A2m Q=30.84l/sQ=46.05l/sQ=60.69l/sQ=75.31l/sQ=90.82l/s

Q=104.76l/sQ=120.67l/sQ=141.01l/s

b- Phase transition

c- Phase submerged flowI II III


1-2 Effect of the discharge on the submergence of the PK-Weir A1


Figure 10. Relative upstream head according relative downstream head (model type A1)


2- Comparison of the results obtained on the different models

1

1.5

2

2.5

3

H*/

H0


Figure 11. Comparison of the effect of submergence between the PK-Weir type A2m , A1 and model PK-Weir (Tullis 2012)

0

0.5

1

0 0.5 1 1.5 2 2.5 3

Hd/H0

PK-Weir A1 Q=142.28l/s

PK-Weir A2m Q=141.01l/s

Courbe de référence PK-Weir (Tullis 2012)


3- Mathematical relationship of the coefficient of submergence


Figure 12. Discharge for submerged Weir


� Rectangular Weir (Villemonte) :

� PK-Weir type A2m :


� PK-Weir type A (Results of physical models HCM) :

��d��

��d��


IV. Conclusion

This study is primarily interested in the effect of the downstream level

on the upstream level in submerged flow conditions. The tests carried out

on two models of PK-Weir have shown that the downstream conditions

can affect the upstream flow of the PK-Weir. This influence has been

demonstrated that it is characterized by a proportional variation between the


y p p

upstream and the downstream whatever the importance of the discharge. It

was also found that the variation of the relative downstream head compared to

the relative upstream head is done in a proportional manner for the

different discharge on the PK-Weir A2m.


The PK-Weir with overhangs continued up to the base (A2m)

seems to be more exposed to the submergence that the PK-Weir standard

type A.

The PK-Weir has the advantage to be better adapted to function


in conditions of submerged flow, however, the linear weir is more

susceptible to submergence. As well, the importance of the effect of the

submergence depends on the type of weir.

Université Mohamed Khider - BISKRA - ALGERIALaboratoire Aménagements Hydrauliques et Environnement

Tel/Fax : 033 73 79 62 Mobile : 062 57 31 24 Email : [email protected]

Documents

Submerged flow regimes of PK-Weir - Labyrinth and piano ... 2nd International Workshop on Labyrinth and Piano Key Weirs Paris - Chatou, France 20-22 November 2013 Sommaire I. Introduction