Dear CFD People,

I would like to learn how many smoothing iterations are necessary before restriction (transversing from fine-to-coarse grid) and after prolongation (transversing from coarse-to-fine grid) while solving Euler and Navier-Stokes equations with (a finite volume scheme, Runge-Kutta time integration, Roe scheme, local time stepping) FAS Multigrid and FMG algorithm.

Regards.

Hi: I come across a case b4 whereby implicit residual smoothing is indeed necessary before the residual is prolonged to fine grid level to ensure multigrid efficiency. However, instead of Roe scheme, I am applying the NVF schemes for convective discretization. For that purpose, 2-3 iters are fine..