Hi,everyone I want to ask a question about the boundary condition adoption in the intermediate velocity for calculation of incompressible N-S flow, using SIMPLE, or Four-steps fractional, pressure correction, velocity correction methods, how to set the BC for intermediate velocity especially in the region where the natural boundary is imposed like -p+du/dn=0? also what's the proper BC for the Poisson equation for the pressure or pressure increment during fractional method? Your any suggestion will be greatly welcome. Hope someone can suggest me some associated classical readings! I'am writing my code by finite element method in fortran, if you want to share some experince in coding with me, I will appreciate your any help.

When you use projection method and solve the poisson equation for pressure update and velocity correction with finite element method, the boundary conditions are imposed implicitly.

Hi, Junseok What's the meaning of 'boundary conditions are imposed implicitly', is this BC formulated from equation? Thanks! Yiling

See the paper, "A numerical method for the incompressible Navier-Stokes equation on an approximate projection"

SIAM J. sci. comput. Vol 17, No. 2, pp. 358-369, 1996.