I am trying to simulate laminar boundary flow over a rectangular cylinder. I am sure the problem has been handled by many researchers. I have searched through the discussion in this forum, and I think I understand the velocity and pressure boundary conditions on left and right edge. But could anyone point out the correct boundary conditions (both velocity and pressure) on the free stream?

Thanks in advance.

i'm looking for boundary conditions of free surface in open channel junction too.if you recieve any answer please send that to my email(varshavian@mehr.sharif.edu) thank you. good luck

i'm looking for boundary conditions of free surface in open channel junction too.if you recieve any answer please send that to my email(varshavian@mehr.sharif.edu) thank you. good luck

For the momentum equation, you can impose traction boundary condition. The traction is from the pressure and surface tension. For position equation (mesh generation equation), in the normal direction, impose velocity zero; in the tangential direction, impose node distributions you want.

Could you be more descriptive what is 'traction' boundary condition? Thanks

traction is n.T, where n is unit normal vector, and T is the stress tensor. On a liquid free surface, t n : T = 0, n n : T = -P + k sigma. where t is unit tangent vector, P is the pressure, k is the first curvature, sigma is the surface tension.