# Boundary condition and Poiseuille flow simulation

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 February 23, 2010, 11:25 Boundary condition and Poiseuille flow simulation #1 Senior Member   Cyprien Join Date: Feb 2010 Location: Stanford University Posts: 299 Rep Power: 18 Hi everybody, I am new with OpenFOAM. I am trying to solve a 2D Poiseuille flow using the icoFoam solver. My geometry and meshing are the following : convertToMeters 0.1; vertices ( (0 0 0) (1 0 0) (1 0.1 0) (0 0.1 0) (0 0 0.01) (1 0 0.01) (1 0.1 0.01) (0 0.1 0.01) ); blocks ( hex (0 1 2 3 4 5 6 7) (40 40 1) simpleGrading (1 1 1) ); edges ( ); patches ( patch inlet ( (0 4 7 3) ) patch outlet ( (1 5 6 2) ) wall fixedWalls ( (3 7 6 2) (1 5 4 0) ) empty frontAndBack ( (0 3 2 1) (4 5 6 7) ) ); mergePatchPairs ( ); // ************************************************** *********************** // I apply an inlet and outlet pressure values with the fixedValue boundary condition. However, I am still looking for the velocity boundary condition type I need to use. Actually, I haven't found the Fluent "velocity outlet" equivalent... Can you help me ?

 February 25, 2010, 06:53 #2 New Member   Tammo Wenterodt Join Date: Mar 2009 Posts: 24 Rep Power: 17 What exactly do you mean by Poisseuille-flow? A laminar channel flow? Then you might want to look here: http://www.cfd-online.com/Forums/ope...utlet-b-c.html //Tammo

 February 26, 2010, 03:49 #3 Senior Member   Cyprien Join Date: Feb 2010 Location: Stanford University Posts: 299 Rep Power: 18 Thank you for your answer. Actually, the BC I looked for was type pressureInletVelocity; value uniform (0 0 0);

 May 12, 2010, 06:24 #4 Senior Member   Emanuele Join Date: Mar 2009 Posts: 110 Rep Power: 17 Can you post your 0/p file?? Thanks in advance Regards

 March 10, 2011, 16:28 Beginner #5 New Member   Join Date: Oct 2010 Posts: 27 Rep Power: 15 Can you please post your 0/p file and 0/U file? I am also trying to simulate a 2D Poiseuille flow using the icoFoam solver. But it is not clear to me which boundary should I use for the U and p? Thanks Last edited by albem; March 10, 2011 at 16:57.

 March 10, 2011, 16:36 #6 New Member   Join Date: Oct 2010 Posts: 27 Rep Power: 15 Sorry I forgot to mention I am using Version: 1.7.1 thanks in advance Alberto Last edited by albem; March 10, 2011 at 16:59.

 March 11, 2011, 14:53 #7 New Member   Join Date: Oct 2010 Posts: 27 Rep Power: 15 I have tried to include the previous recommendations for the 2D Poiseuille flow and this was the result using icoFoam Time = 0.5 Courant Number mean: nan max: nan DILUPBiCG: Solving for Ux: solution singularity DILUPBiCG: Solving for Uy: solution singularity DICPCG: Solving for p: solution singularity time step continuity errors : sum local = nan, global = nan, cumulative = nan DICPCG: Solving for p: solution singularity time step continuity errors : sum local = nan, global = nan, cumulative = nan ExecutionTime = 2.3 s ClockTime = 3 s End This is my /0/U file /*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 1.7.1 | | \\ / A nd | Web: www.OpenFOAM.com | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volVectorField; object U; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 1 -1 0 0 0 0]; internalField uniform (0 0 0); boundaryField { inlet { type pressureInletVelocity; value uniform (1 0 0); } outlet { type pressureInletVelocity; value uniform (1 0 0); } fixedWalls { type fixedValue; value uniform (0 0 0); } frontAndBack { type empty; } } // ************************************************** *********************** // Last edited by albem; March 11, 2011 at 18:19.

 Tags boundary condition, poiseuille flow, simulation