AMG+FVM

Isa

Hello everybody:

I would like to point out some questions about algebraic multigrid (AMG) applied to an algorithm that solves the uncoupled Navier-Stokes equations with pressure poisson equation with a finite volume method (FVM).

(I have been working with the lid driven cavity benchmark)

I only apply AMG over the pressure poisson equation and, in each iteration, I must calculate the Galerkin operators since the coefficients of the pressure matrix changes each time, so it takes a long time. And although, the number of iterations for the convergence goes down with AMG, the total time of the algorithm increases.

So I think, AMG is better for FEM (because the Galerkin operators only have to be calculated one time) instead of FVM, am I right, if not why not?

Thank-you very much for your time and for your replies. I would like to say that the information about multigrid in this page is really good,congratulations! Isa