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-   -   Boundary condition and Poiseuille flow simulation (https://www.cfd-online.com/Forums/openfoam/72981-boundary-condition-poiseuille-flow-simulation.html)

 Cyp February 23, 2010 12:25

Boundary condition and Poiseuille flow simulation

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 ?

 wenterodt February 25, 2010 07:53

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

 Cyp February 26, 2010 04:49

Actually, the BC I looked for was

type pressureInletVelocity;
value uniform (0 0 0);

 nuovodna May 12, 2010 06:24

Regards

 albem March 10, 2011 17:28

Beginner

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

 albem March 10, 2011 17:36

Sorry I forgot to mention I am using Version: 1.7.1

Alberto

 albem March 11, 2011 15:53

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;
}
}

// ************************************************** *********************** //

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