Unsteady laminar flow around cylinder with CS
- Alicia
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14 years 4 days ago #4124
by Alicia
Replied by Alicia on topic Re:Unsteady laminar flow around cylinder with CS
[/quote]I don't know enough about CS to properly diagnose the problem, but how is convergence (in 'listings' file) ?[/quote]
-> What do you mean by "how is the convergence' ? I had a look at the listing file, and for each time step all variables are under the convergence criteria I set in the GUI. The 'derive' column (if I understood well, it's something like a relative variation of the variable between two time steps) is always very low (1e-1 for pressure and around 1e-5 or below for the velocity components).
[/quote]Do you run the simulation long enough for the vortex shredding to appear? The ones in mine don't appear until 20 (video) seconds into the simulation.[/quote]
-> I tried with different number of time steps. I ran a calculation with 3000 time steps, each time step being 0,4 s (so the pysical time at the end of the calculation was 1200s, and I still didn't have any vortex shedding (for this one I was not sure about the initialization, but it shouldn't have such a big impact). The last calculation I ran was for 50 time steps (20s), and the flow didn't show any vortex shedding (for my Re, the period of the shedding is around 10s, so I should have at least one vortex away from the cylinder at 20s, which isn't...).
Thank you again for your answers, it's always helpful !
I will try the code saturne support contact if I really can't come up with something !
Post edited by: Alicia, at: 2010/04/15 19:35<br /><br />Post edited by: Alicia, at: 2010/04/15 19:35
-> What do you mean by "how is the convergence' ? I had a look at the listing file, and for each time step all variables are under the convergence criteria I set in the GUI. The 'derive' column (if I understood well, it's something like a relative variation of the variable between two time steps) is always very low (1e-1 for pressure and around 1e-5 or below for the velocity components).
[/quote]Do you run the simulation long enough for the vortex shredding to appear? The ones in mine don't appear until 20 (video) seconds into the simulation.[/quote]
-> I tried with different number of time steps. I ran a calculation with 3000 time steps, each time step being 0,4 s (so the pysical time at the end of the calculation was 1200s, and I still didn't have any vortex shedding (for this one I was not sure about the initialization, but it shouldn't have such a big impact). The last calculation I ran was for 50 time steps (20s), and the flow didn't show any vortex shedding (for my Re, the period of the shedding is around 10s, so I should have at least one vortex away from the cylinder at 20s, which isn't...).
Thank you again for your answers, it's always helpful !
I will try the code saturne support contact if I really can't come up with something !
Post edited by: Alicia, at: 2010/04/15 19:35<br /><br />Post edited by: Alicia, at: 2010/04/15 19:35
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