Coupled solver and multigrid
 

Hi,

Suppose we solve the momentum equation and continuation equation in each element sequencely ( which is called coupled solver), I want to apply the multigrid technique into this solver to accelarate the convergence, the discretization on the fine grid is via FEM ( Q1~/Q0 elememt), I have tried both algeraic and geometric multigrid, but both of them don't work.

I want to ask the following questions:

1. How to make prolongation of the velcoity and pressure coeficients( Algebraic Multigrid)?

2. How to transfer the residual ( geometric multigrid)?

3. Are there any one who have experience in this area?

I am desperatly struggling with these qustions (kidding) , anyone who can give some clues are sincerely appreciated.

Thanks

Hongliang Yang