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 Lionel S. August 5, 2007 16:38

Pressure boundary conditions

Hi all,

First I thought that if you have a boundary condition which imposes pressure only, the velocity at that point is taken as being the same as the neighbouring cell. In fact it imposes

near to the pressure (outflow) boundary, but I supposed that for many flows, it's not a problem.

Now I wonder if solving the unknowns for boundary conditions would make the system a little less stiff.

The problem is: I already have 3 equations (Navier Stokes X and Y and continuity) for each cell, as well as 3 unknowns (X and Y velocities and P). I cannot solve it if I have additional unknowns for boundary conditions. The problem for boundary conditions imposing velocity only is the same.

Some people told me to read Versteeg and Malalasekera, but I didn't find exactly what I search.

Any idea ? Thanx in advance

 pankaj saha August 24, 2007 18:03

Re: Pressure boundary conditions

for pressure b.c----

on the outflow---p=0 and any other plane normal gradient of p is =0

try it.

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