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Hi everyone,

I'm really struggling with my simulation and need some help. I have a large river simulation with 3 Q-Boundaries, where the water flows in and an h-boundary and prescribed h for the outlet.

The overall water level of the simulation results are fine, but towards the outlet the water level rises and bevore the outlet the water level fluctuated. Also it does not reach a steady state and fluctuates around the end. The water level is supposed to be around 101.97 m.

The prescribed h I used is definitely correct and with other simulation softwares it worked perfectly.

I have attached the .cas-file and a screenshot of the free surface elevation along the river towards the outlet.

Do you have any idea why this could be the case?

Thank you in advance for your support!

Hi
Mesh size vs time step and poor convergence criteria?

Regards
PS: Think to upgrade your profile

Thanks for the fast reply!

You mean that I have to choose a smaller time step because of the large mesh?

And how can I improve the convergence criteria?

(Sorry, I'm quite new to Telemac)

Regards

No
We don't have any idea of your mesh size near the boundary, nor the expected velocities...
We just know the time step which is 10s so maybe a problem if this leads to very high CFL.
THe other aspect is 1E-3 for accuracy which is poor ...