open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi,

I wanted to model a weir in a river. All the relevant data are uploaded in the zip file.
I have two cases with each having an inflow and outflow boundary conditions and a weir defined as an island in between(case one) and two separate mesh(case two). The inflow is hydrograph with constant discharge of 6 m3/s after 30minutes. The outflow BC is constant WSP of 48.8m.

One can see the water flow through the upstream of weirs but never reach downstream sides in the results.
However if I increase the Outflow BC to fictive value (e.g. 50m), first this water enters the mesh and reach the weirs downstream sides and the weir flow is activated.
(This can be seen clearly in the results of velocity.)
If I want to model it with a Stage Discharge Curve no water enters the mesh from outflow BC and
the weirs never get activated and no flow occurs.
Can you please explain why the water does not flow from Weirs upstream to downstream in above cases.

Kind Regards
Sandip

Hi
Weirs works like a boundary (as default option) and then need to have some water at the downstream side to allow imposing the discharge...
try to modify locally the bottom to have a local "pool" with water at the initial step and this should solve your problem...

Regards

Hi again,

Thanks for your suggestion. The water flow from the weirs to the downstream however my outflow is extremely high (37 m3/s) despite the inflow being 6 m3/s. From where did these water come from? I have attached the listing here with.

ITERATION 283500 TIME: 1 H 59 MIN 58.7748 S ( 7198.7748 S)
LIQUID BOUNDARY: Q(2) = 6.0000000000000000

---

DIFFUSION-PROPAGATION STEP
TIME-STEP: 2.3941399785188527E-002

---

BALANCE OF WATER VOLUME
VOLUME IN THE DOMAIN : 25692.87 M3
FLUX BOUNDARY 1: -38.56242 M3/S ( >0 : ENTERING <0 : EXITING )
FLUX BOUNDARY 2: 6.000000 M3/S ( >0 : ENTERING <0 : EXITING )
RELATIVE ERROR IN VOLUME AT T = 7199. S : -0.2473096E-04


Kind regards
Sandip

Hi,

I am still waiting for answer to above mentioned question.

kind regards