open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello, everyone

I am a beginner at TELEMAC and SISYPHE and i am trying to implement a simulation of sediment transportation in a steady flow along a straight channel.

After successfully running my calculations for the hydrodynamic model in telemac, i tried to implement the coupling with sisyphe, but i get the following error message:

DEBIMP: PROBLEM ON BOUNDARY NUMBER 2
GIVE A VELOCITY PROFILE
IN THE BOUNDARY CONDITIONS FILE
OR CHECK THE WATER DEPTHS.
OTHER POSSIBLE CAUSE:
SUPERCRITICAL ENTRY WITH FREE DEPTH
IN THIS CASE GIVE A POSITIVE DEPTH
IN THE INITIAL CONDITIONS
OR PRESCRIBE THE DEPTH AT THE ENTRANCE.

I know this problem has been studied in multiple posts on the forum, but what I dont'understand is that my hydrodynamic model works perfectly, and when i remove the coupling with sisyphe in the TELEMAC2D steering file, the problem disappears. Therefore it would seem that something in the SISYPHE steering file, or in the coupling itself is the cause of this error.

I am using the CONTINUED COMPUTATION option for the telemac calculations with a constant discharge of 0.019 m3/s (BC type 455) at the upstream boundary , and i checked in the previous results file that the water depth along this boundary is acceptable, and so on for the velocity.

I tried to comment one by one the keywords in the sisyphe steering file that i thought could cause this issue, but i was unable to find a solution.

Could anyone help me to find the origin of the problem, or explain me what i did wrong in the implementation of the coupling?

I attached the main files of my simulation , along with a printscreen of my previous results file.

Thanks in advance,best regards,

Jonas

Hello Jonas,

As a beginner I advise you to take a look at examples and validation documentation to understand how the software works.

On other hand, I see into your boundary conditions file (you use the same for both Telemac2D and Sisyphe) that you set LITBOR=2 in your prescribed boundaries as follows:

5 4 4 0.000 0.000 0.000 0.000 2 0.000 0.000 0.000 11228 414 # Downstream
4 5 5 0.000 0.000 0.000 0.000 2 0.000 0.000 0.000 5615 855 # Upstream

Reminder that LITBOR=2 means close boundary (wall). Change it to 4 as follows:

5 4 4 0.000 0.000 0.000 0.000 4 0.000 0.000 0.000 11228 414 # Downstream
4 5 5 0.000 0.000 0.000 0.000 4 0.000 0.000 0.000 5615 855 # Upstream

That should work. Nevertheless, in case it does not work, I'd need all your files to run your model on my computer and have a better approach.

I hope this helps.

Cheers,
José Andrés.

Hello Jose,

Thank you for your answer.
I modified the boundary conditions file as you suggested and it now works.
Does this mean that declaring a close wall for tracers in the BC file (LITBOR=2) implies that this boundary is actually a physical wall for the flow ?

I initially set the Upstream and Downstream boundary conditions as closed wall for tracers because i am only interested in the erosion inside my channel.

However thank you for your help and your advices.

Best regards,

Jonas