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SIMPLE algorithm, P and u at inletHello everybody,
I'm solving the N-S equations using the SIMPLE algorithm. It converge fine and quite fast when I set dirichlet boundary conditions for the velocity at inlet and outlet of the channel, but I have problems when I want to set dirichlet B.C. for both pressure and velocity at the channel inlet. I'm solving the u-momentum equation at the main control volume interfaces, and the pressure correction equation at the central nodes. how should I set the pressure value on the first node, in order to fulfill the inlet pressure condition? I think the problem is there. thanks in advance Mauri |

Hello Mauri,
I am having the same problem. My code works almost perfect for velocity inlet but I have problems when I try pressure BCs. Were you able to come up with a solution to set pressure inlet & outlet to your boundary? |

Quote:
Imposing a neumann BC for velocity at the outlet is a better option. Quote:
If you want to impose a dirichlet BC for pressure at inlet then use neumann BC for velocity. |

Hi!
1. The inflow conditions will be u=u_inlet, v=0, dp/dx = 0. and for outlet, we can use fully developed outflow BC, (by making few assumptions). Fully outflow BC is du/dx = 0, dv/dx = 0 and drichlette BC on pressure, ie P=0. 2.The boundaries are always given at physical domain. I believe you are familiar with concept of fictitious cell method for imposing BCs(ref. veerstag & malasekra, or milovan Peric's CFD book). if U or V lies on the "PHYSICAL BOUNDARY" of domain, leave it as it is. If the value lies at fictitious cell, then impose P_boundary = (P_fictitious+P_internal)/2 and make P_b = 0. Hope this helps. In case of doubts, please reply back |

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