Re: a question

Z. Chang

Dear all CFD Web friends,

Would you please answer the following questions?

For given differential eqution: Lu=f where L is a nonlinear operator

In two-level V-cycle Multigrid algorithm(i.e. smoothing on fine mesh,correctin on coarse mesh)

1) when performing coarse-grid correction, why one always choose the same oprator to solve the defect equation?

if choose different nonlinear operator(e.g. lower order

operator G), what difference can be cause(e.g. correction magnitude and efficiency of the approach)?

2) what is their definiton? the trancation error, defect/residual and relative trancation error(between fine and coarse grid).

what is the difference between the trancation error and defect/residual ?

Thanks!

Z. Chang