•existing solver for the incompressible Navier-Stokes equations:
 •using the projection method, eq. for the velocity and pressure are solved sequentially at each time step
 •using Galerkin finite element method to discretize in space
 •the pressure Poisson eq. is preconditioned with a mixed
 additive/multiplicative domain
 decomposition method: one iteration of
 overlapping Schwartz combined with a coarse grid
 correction