open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello,

I am currently simulating a meandering river by telemac2d. However, I faced some problems with my water depth and velocity. At the riverbank, some negative depth occurred in the results and the Froude number is extremely high in some points (as shown in the photo). And the flow velocity is unstable and discontinuous in the river channel as well. I am struggling with this issue and hope anyone can help me. I attached my cas. file.

Regards
LIN

Additionally, I set upstream boundary as prescribed q and downstream as prescibed h. The liquid boundary file is attached.

When does this velocity instability occur in your simulation. You use a previous computation file, is this the result of a constant flow towards equilibrium state and does that state match your first Q and H values?

Cheers,
Patrick

Hello Patrick,

Thank you for your advise. I have already fixed this issue by reducing my time step. The previous time step is too high for simulating the my river case.

Regards
LIN

Hello Lin,

As written in the TELEMAC-2D user manual, if you do not want to have negative water depth, you should use TREATMENT OF NEGATIVE DEPTHS = 2.

Hope this helps,

Chi-Tuan

Hello Chi-Tuan,

Your advise is very useful. I used the negative depths=2 and finally there area no negative depth in my result. Thank you.

Regards
LIN