[Lise]

NOTE: sorry in advance if my english isn't perfect, I swear I do my best

Hi everyone!

I'm working on the Von Karman Vortex Street appearing behind a cylinder put in an airflow.

Used parameters :
- Unsteady flow (implicit scheme + second order scheme)
- Ideal gas
- Turbulent k-omega SST model
- Coupled flow

I'm wondering why I have to enter the time-step AND the CFL, since the velocity is calculated and the dx is provided with the mesh.
Why doesn't the time-step set the CFL?

Moreover, I thought an implicit scheme implied no CFL condition (always stable), why is there one in this case?

Last question: my best results come with a CFL = 40, and the solution fully diverges when CFL=1, I would have think the opposite would occur (by definition of the CFL). Can someone give me a clue about the reason for that?

Thanks in advance!

[ping]

for unsteady the cfl sets the pseudo time step for the inner iterations within the outer time steps - see the user guide under pseudo time step