i am solving a foam flow problem.initially i gave a boundary condition of no slip on the bubble surfaces and i got reasonable answer.but when i gave a free slip bounday condition the solution is not converging. i am getting absurd results. in both cases at the inlet and outlet i gave pressure boundary conditions.

Hi,

why not try a mass flow inlet and static pressure outlet boundary conditions. This is a more stable set-up than pressure-pressure. Once a solution is extablished in the range desired a switch to pressure-pressure may work.

Regards,

Bak_Flow

Are you specifying static pressure inlet / static pressure outlet or total pressure inlet / static pressure outlet? If the former then of course there will be convergence difficulties because you are attempting to solve a case with an imposed pressure gradient, yet no means to balance that pressure gradient (i.e. you have removed viscous effects at the walls).

Neale.

BAK_FLOW AND Neale, i will try the problem as you suggested and check whether i am getting any convergence. thank you for your response.

regards sreenivas