why interDyMFoam does not support backward ddt scheme?
 

Dear Foamer,

I would like to use backward second order time discretization in interDyMFoam, but the solver doest not support this time scheme.

Could someone explain the reason for that?

Many Thanks,
Yage

I found that the interDyMFoam support Crank-Nicolson (CN) scheme and I set the weighing factor to 1 for fully second order accuracy.

But the alphasubcycle must be 1 in this case.

Any idea about the reason?

hello,

This may come from the fact the backward are not a bounded scheme, and MULES need it, or that MULES aren't coded to use backward.
CN just need current and old time, so sub-cycling used in MULES may not be usable. Same for backward.

regards,
olivier

Thanks for your answear

and any suggestion for which one to use, 1st order ddt + sub-cycling or 2nd order ddt without sub-cycling?

Regards,
Yage

hello,

I would say first order for a RANS may be enough, and 2nd order with lower time step for more fine RANS/ LES case.

regards,
olivier

Thanks for the suggestion