code_saturne User's Forum

Hello,

In code_Saturne v5, what I understand is that the variable time step option cannot be used with LES, since second order time scheme in automatically activated and does not support it.
My question: is there a way to use a CFL driven time step with LES simulations? For example can I somehow switch to first order time scheme?

Thank you very much.
Best regards,
Daniele

Hello,

You may try first setting ischtp to 1 in cs_user_parameters.f90 (in usipsu).

You also need to set the time step options (idtvar = 1, ...) in the same user subroutine in this case, as the GUI assumes LES implies a 2nd-order time scheme.

If this is not enough, you may have to modify the code, by deactivate the automatic setting in varpos.f90 (set ischtp to 1 instead of 2).

In any case I do not think running an LES with a first order time scheme is recommended, so interpreting the results may be tricky/misleading.

Best regards,

Yvan