[dnl_xr]

Hei,


for my laminar flow through a pipe I have to implement a fully developed inlet velocity profile. I couldn't find any preset boundarie conditions. so I found out that I have to use codedFixedValue. Unfortunately near the wall the gradient differs from the rest of the parabola (picture below).

here is my code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2312                                 |
|   \\  /    A nd           | Website:  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            fixedValue;
        value             uniform (1 0 0);
        
    }
    */
    
    inlet
    {
        type            codedFixedValue;
        value           uniform (0 0 0);
        
        name inletLaminarProfil;
        code
        #{
             const fvPatch& boundaryPatch = patch(); //generic
             const vectorField& Cf = boundaryPatch.Cf(); //generic
             vectorField& field = *this; //generic

             const scalar yc      =     0; // definition of the center y coordinate
             const scalar rpipe    =     0.00025; // definition of the pipe radius
             const scalar Umax  =     0.596; // definition of the maximum velocity Re=1

             forAll(Cf, faceI) // loop over all the patch faces
             {
//                const scalar x = Cf[faceI].x(); // x coordinate of the faces i
                const scalar y = Cf[faceI].y(); // y coordinate of the faces i
                const scalar z = Cf[faceI].z(); // z coordinate of the faces i
                const scalar radius = pow((y-yc)*(y-yc)+z*z,0.5); // compute radius from center patch

        field[faceI] = vector( Umax *(1-pow(radius/rpipe,2)), 0, 0); // define velocity value on the face i
             }

        #};
    }


    outlet
    {
        type            zeroGradient;
    }

    wall
    {
        type            noSlip;
    }
    
    
    "(front|back)"
    {
        type            wedge;
    }
    
}


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

I wonder if I did something wrong. Can someone help me please?