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July 9, 2012, 10:11
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pressure boundary conditions
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#1 |
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Member
G. S.
Join Date: Nov 2010
Posts: 54
Rep Power: 15  |
Hi cfd colleagues,
What are the pressure boundary conditions I have to set for the following boundaries?: 1) Flow entering through a boundary. 2) Flow exiting through a boundary (corrected mass flow). 3) Wall with no slip condition. For (3) I use isolated boundary for pressure equation (no diffusion through boundary), but I'm not sure what do I have to use for (1) and (2) because I'm confuse if I have to set 0 value for pressure nodes at the exit (let's say a pipe or duct exit) or is it a no diffusion boundary condition on pressure equation. This is a collocated variable CVFEM scheme on triangular grids... Best regards... |
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July 9, 2012, 10:30
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#2 |
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Senior Member
Julio Mendez
Join Date: Apr 2009
Location: Fairburn, GA. USA
Posts: 290
Rep Power: 18  |
Dear Gerardo.
In your first question, you may use dinamic pressure. In your second question, I would use 0, because I assume your are using "outflow" as a result, you will have the other pressure, from an explicit way. At any wall the pressure you selecte is the same as you define as a pressure reference! Greetings !!!! from INELMECA!! |
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July 9, 2012, 11:46
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#3 | |
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Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,764
Rep Power: 71 |
Quote:
depends on your case ... are you solving compressible of incompressible flow? The mathematical problem is different ... |
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July 9, 2012, 18:17
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#4 | |
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Member
G. S.
Join Date: Nov 2010
Posts: 54
Rep Power: 15 |
Quote:
 ..Thanks in advance FMDENARO... |
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July 10, 2012, 03:41
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#5 |
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Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,764
Rep Power: 71 |
this paper can give useful suggestions
Poinsot T. et Lele S. (1992). Boundary conditions for direct simulations of compressible reacting flows. Journal of Computational Physics. 101, 1, 104-129. otherwise, for incompressible flows, when the pressure equation is derived from the continuity constraint (divergence-free velocity field), the boundary conditions for the pressure are derived from the Hodge decomposition |
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| Tags |
| boundary conditions, collocated, cvfem, pressure |
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