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Hello,

I'm running a simulation with one inflow and two outlet. When I launch a simulation with a big discharge (7793 m3/s), I see some variation of the discharge mesured by control sections in my model. This variation is accompanied by fluctuation of the free surface, velocity and Courant Number.





As you can see, I imposed a steady state with a liquid boundary file and I prescribed h downstream.
Have you ever encountered this problem?

Best regards.

Jules

Hello

This is not a problem, Section A looks very stable since it is close to the inlet. For the remaining sections, the flow can behave under the effects of turbulence, wetting and drying and especially the presence of the confluence upstream sections C and D. these fluctuations could be with physical meannings.

If you want more stable result you can increase velocity diffusivity (VELOCITY DIFFUSIVITY).

with my best regards

Riadh ATA

Hello Riadh,

I already put the velocity diffusivity to 0.1 for this simulation. I'm trying another with FREE SURFACE GRADIENT COMPATIBILITY to 0 instead 0.9 but it seems not to change anything.

Anyway, I focused on a numerical problem but may be this has a physical meaning.


Best regards.

Jules