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pressure boundary conditionsHi 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... |

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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depends on your case ... are you solving compressible of incompressible flow? The mathematical problem is different ... |

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Thanks in advance FMDENARO... |

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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