Simulation in primitive variables for incompressible flow with pressure Neumann condition

We develope a velocity-pressure algorithm, in primitive variables and finite differences, for imcompressible viscous flow with a Neumann pressure boundary condition. The pressure field is initialized by least-squares and up-dated from the Poisson equation in one step without iteration. Simulations whit the square cavity problem were made for several Reynolds numbers. It was obtained the expected displacement of cenral vortex and the apperance of secondary and terciary eddies. Different geometry ratios for the cavity were also considered. Simulations for a 3D cavity were carried out with an Adams-Bashforth metho