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TOPIC: Problem of water line before a weir

Problem of water line before a weir 9 years 1 month ago #18385

  • arrighi
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Hello,

I want to modelize in a steady state a portion of a river which contains a weir.
I impose a constante discharge upstream (Q100) and a constant water level downstream.

For the small discharge (about 0.1*Q100), the water line is ok. But for high discharge (about 0.25*Q100), the water line increase before the weir whereas the regime is subcritical (Fr<1). I attached to this post a picture of the water line.

I thought that it was a problem of stability of the model.
I have tried to modify these parameters : mesh, planimetrage, time step, but nothing works.

Does anyone know how to solve this problem ?

Thanks in advance

Claire
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Problem of water line before a weir 9 years 1 month ago #18386

  • c.coulet
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Did you make a test with the steady kernel?
You wrote that Fr<1 but could you add the value on the graph?

Regards
Christophe
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Problem of water line before a weir 9 years 1 month ago #18387

  • arrighi
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Yes, the result i have shown was with the steady kernel.

I attached the graph of the Froude.

Thanks you

Claire
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Problem of water line before a weir 9 years 1 month ago #18389

  • c.coulet
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Hi

It could be due to the mesh size. If you refine your pesh, you will probably have a better result.
Maybe you could post your model in order to check some parameters.

Regards
Christophe
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