hi,

i'm doing pseudo-compressibility pressure correction in transient low R_e flow in a tube (2D). how do I choose optimal ratio between dt for velocity update and (pseudo) dt for pressure correction? in particular: is it better to do more velocity corrections and few pressure corrections or vice versa?

thank you.

If you are using pseudo-compressibility method, then pressure is also updated via time or pseudo time marching, then you do the same times of corrections to both V and P.

you mean, correct velocity, correct pressure and again, in a loop? yes, that is clear, but what about "dt", how do I set optimal relation between two delta t's for both explicit time marching...?

thanks domi

Years Ago AIAA Journal had papers discussing pseudo time sep and physical time step. The pseuodtime step has the meaning of relaxation factor, it can be larger than a nondimensional physical Dt. may be 10 times up, I remebered. If the inner iteration is implicit can be 10^12 up. (== discarding it at all)

read paper on dual time step approch , try one by Yoon and Jameson on LU-SSOR for eular and NS eqn and there are some more by Jameson that explains dual time stepping approch quite well.

Hello everyone,

Is there anybody who are using IMF(Implicit Multifield Model of Harlow & Amsden) technique for their studies?I want to ask some questions.

thanks