MULTIGRID SOLUTION OF THE INCOMPRESSIBLE NAVIER-STOKES EQUATIONS IN GENERAL COORDINATES

Galerkin coarse grid approximation (GCA) in multigrid methods is investigated for the incompressible Navier-Stokes equations in general coordinates. An efficient algorithm performing GCA is presented. The behavior of coarse grid matrices is studied under GCA with different transfer operators. For square and L-shaped driven cavity problems, the performance of the multigrid method using different combinations of transfer operators for the computation of coarse grid matrices and of coarse grid correction is investigated. Further computations are carried out in general coordinates for a channel flow problem with backward facing step in three dimensions.