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-   -   Boundary Conditions on free surface (http://www.cfd-online.com/Forums/main/5484-boundary-conditions-free-surface.html)

Mohammed Anwer December 2, 2002 02:15

Boundary Conditions on free surface
 
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.

varshavian December 2, 2002 04:22

Re: Boundary Conditions on free surface
 
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

varshavian December 2, 2002 04:34

Re: Boundary Conditions on free surface
 
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

xueying December 2, 2002 12:35

Re: Boundary Conditions on free surface
 
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.

Mohammed Anwer December 2, 2002 18:47

Re: Boundary Conditions on free surface
 
Could you be more descriptive what is 'traction' boundary condition? Thanks

xueying December 3, 2002 13:04

Re: Boundary Conditions on free surface
 
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.


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