code_saturne User's Forum

Hello,

I try to use a restart point with syrthes coupling for having stationnary temperature fields. Only with CS I have realistic results with a frozen velocity field and compute the temperature in fluid with large time steps.
If I try to do the same calculation including syrthes coupling I have no more realistic temperature fields. It seems that the frozen velocity field is not taken in account in the temperature distribution (it seems the fluid is not moving like a solid phase). however I can visualize the frozen velocity in the fluid domain.

The coupling case is running fine without restart for small time steps.

Any suggestions about this problem?

Best regards

Julien

Hello,

This is strange. Did you test restarts without a froze field ? Did you configure the restart on the Syrthes side ?

Regards,

Yvan

Hello,

Yes the restart file is also done for syrthes. Maybe my time step size is too large with the restart calculation. I have 0.01 sec for a Courant number less to 50 with Naviers Stockes and I change for 5 sec for the temperature calculation with velicity and pressure frozen fields. Is there a rule to limit the time step size in such case?

Best regards

Julien

Hello,

No, there is no specific recommendation. A restart should "just work". I have not tested restarts with Syrthes coupling in a specific manner recently, but users who run major studies should use it regularly (as most computation queues are limited to 2 or 3 days, and long unsteady computations on large meshes require more than that), and have not reported issues.

If you have a small test case you can post, I'll try to run it.

Best regards,

Yvan

Hello,

I post my case but I can not add the restart point because it's larger than 10MB even compressed.
I have done 200 iterations of 0.01 sec to have the restart point and continue until this point for several hundreds iterations of 0.5 sec (you can see my files), I have the same problem than for larger time steps of 5 sec.

Thank you for your help.

Best regards

Julien

Hello,

I redo the the case in exploiting symetry axis to reduce the size of the files. The restart file is now included in the joined file.

Best regards

Julien

Hello,

Have you some time to remake the restart case?

Thank you for your help

Best regards

Julien

Hello,

Not yet, and I won't be able to test it before next week.

Regards,

Yvan

Hello Yvan,

Have you some time to take a look to my restart problem?

Thank you

Best regards

Julien

Hello,

Sorry, no, I have not found the time to check this yet. I'm keeping it not too far from the top of my TODO list.

Regards,

Yvan