Search found 4108 matches

by Yvan Fournier
Sat Jun 22, 2024 4:49 pm
Forum: code_saturne usage
Topic: problem with initialization from 3D postprocessing
Replies: 1
Views: 60

Re: problem with initialization from 3D postprocessing

Hello, In you case, be careful with checks on field ids. You are using field id 2 for velocity, while the id is usually 1, and testing relative to a field's name is usually safer. Also, an more importantly, you set n_remapper_fields = 4 but define only 2 field names to remap. This is probably what c...
by Yvan Fournier
Wed Jun 19, 2024 12:56 am
Forum: code_saturne usage
Topic: Calculating Velocity Gradient in Post-Processing
Replies: 5
Views: 248

Re: Calculating Velocity Gradient in Post-Processing

Hello, I have not looked at your files yet, but if you suspect a memory leak, add export CS_MEM_LOG=memtrace.log In you execution environment, and when the code runs, it will log all allocations and frees using BFT_MALLOC and BFT_FREE. Run a few iterations, check the list of non-freed variables at t...
by Yvan Fournier
Mon Jun 17, 2024 2:32 am
Forum: code_saturne usage
Topic: Restart not taken into account in v7
Replies: 13
Views: 21277

Re: Restart not taken into account in v7

Hello, I don't use the cs_user_scripts.py for this very often, and for restarting without the GUI, the "auto restart' (which automatically chooses the restart with the latest timestamp) is more practical, but before checking in more detail, can you simply try : domain.restart_input = 'RESU/2024...
by Yvan Fournier
Wed Jun 12, 2024 1:16 am
Forum: code_saturne usage
Topic: Pressure Checkerboard Patterns in Vehicle Aerodynamics Simulations
Replies: 5
Views: 577

Re: Pressure Checkerboard Patterns in Vehicle Aerodynamics Simulations

Hello, The sensitivity to the time step is a headache for us too, though recurring posts on this forum are quite interesting, as they add important knowledge and insight, and this issue is often forgotten, as it is much more sensitive for some types of computations than for others (for example a use...
by Yvan Fournier
Thu Jun 06, 2024 1:12 am
Forum: code_saturne usage
Topic: Pressure Checkerboard Patterns in Vehicle Aerodynamics Simulations
Replies: 5
Views: 577

Re: Pressure Checkerboard Patterns in Vehicle Aerodynamics Simulations

Hello, I mentioned your post to other colleagues who have more expertise in the numerics of the code, and I'll remind them to check, but I know of no option more relevant than adjusting rcfact, using a local time step (pseudo-steady option), or changing the mesh. In you listed options, I do not see ...
by Yvan Fournier
Fri May 31, 2024 12:33 pm
Forum: code_saturne usage
Topic: Pressure Checkerboard Patterns in Vehicle Aerodynamics Simulations
Replies: 5
Views: 577

Re: Pressure Checkerboard Patterns in Vehicle Aerodynamics Simulations

Hello, What CFL number do you have ? Checkerboarding can appear in areas where the time step is very small relative to the mesh size and velocoty, so that the Rhie&Chow coupling (which is unfortunately sensitive to the time step) becomes less effective. I am not aware of checkerboarding in other...
by Yvan Fournier
Fri May 24, 2024 9:50 pm
Forum: code_saturne usage
Topic: Second-Order Temporal Discretization Except for Turbulence Model Equations
Replies: 6
Views: 847

Re: Second-Order Temporal Discretization Except for Turbulence Model Equations

Hello,

I asked a colleague, who told me trying to force 2nd order this way is risky and might ne behave well, and that a PhD student might be looking into this soon, but have no more details.

I'll keep you updated if I get more info on what can be done.

Best regards,

Yvan
by Yvan Fournier
Fri May 24, 2024 9:47 pm
Forum: code_saturne usage
Topic: Steady-Compressible flow
Replies: 6
Views: 3677

Re: Steady-Compressible flow

Hello, Yes, your setting seems OK. I am not sure the pseudo-steady algorithm matches that on your reference, as I am not familiar with the book. It would be interesting to compare. In our case, the code simply adjusts the time step in each cell so as to try to target a CFL of 1. The reference time s...
by Yvan Fournier
Sun May 19, 2024 2:43 pm
Forum: code_saturne usage
Topic: model validation
Replies: 5
Views: 649

Re: model validation

Hello, If you get different results each time, there may be some memory corruption, which indicates a bug... How large is your test case ? If it is not too big, I would be interested in running it under a tool such as Valgrind or a build using AdressSanitizer to check for a bug in code_saturne... If...
by Yvan Fournier
Sat May 18, 2024 12:33 am
Forum: code_saturne usage
Topic: Second-Order Temporal Discretization Except for Turbulence Model Equations
Replies: 6
Views: 847

Re: Second-Order Temporal Discretization Except for Turbulence Model Equations

Hello,

Any detailed feedback on this is very welcome :-)

Best regards,

Yvan