[Fouch]

Hi,


I am running a simulation of a radial fan with simpleFoam. I use "forces" library to compute the torque on the shaft.
The problem is I get around 3 x the expected torque. I really don't understand because I reached the expect result on other calculation but this one.


I am wondering if it could come from the turbulences parameters ?



If anybody has an idea ???


fvSolution

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v1912                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
    "(p|p_rgh|pcorr)"
    {
        solver           GAMG;
        tolerance        1e-7;
        relTol           0.00001;
        minIter          5;
        maxIter          100;
        smoother         GaussSeidel; // DIC; //DICGaussSeidel; //FDIC;
        nPreSweeps       1;
        nPostSweeps      3;
        nFinestSweeps    3;
        scaleCorrection true; 
        directSolveCoarsest false;
        cacheAgglomeration on;
        nCellsInCoarsestLevel 50;    // 500
        agglomerator     faceAreaPair;
        mergeLevels      1;    // 3
    }

    "(pFinal|p_rghFinal|pcorrFinal)"
    {
        $p;
        relTol          0;
    }

    U
    {
        solver          smoothSolver;
        smoother        GaussSeidel;
        tolerance       1e-20;
        relTol          0.00001;
        maxIter          50;
        minIter          5;
    }

    "(k|omega)"
    {
        solver          smoothSolver;
        smoother        GaussSeidel;
        tolerance       1e-20;
        relTol          0.0000001;
        maxIter          50;
        minIter          5;
    }

}

SIMPLE
{
    nNonOrthogonalCorrectors 3;
    consistent yes;
    pRefCell     0;
    pRefValue    0;
    nCorrectors 1;
    
    residualControl
    {
        p           1e-3;
        Uz           1e-3;
        omega        1e-3;
        k            1e-3;
    }
}

relaxationFactors
{
    fields
    {
        p               0.4;
    }
    equations
    {
        U               0.7;
        k               0.5;
        omega           0.5;
    }
}

cache
{
    grad(U);
}

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

controlDict

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v1912                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

saveIter 50;

application     simpleFoam;

startFrom       startTime;
startTime       0;
stopAt          endTime;
endTime         500;
deltaT          1;
writeControl    timeStep;
writeInterval   $saveIter;
purgeWrite      0;
writeFormat     ascii;
writePrecision  7;
writeCompression off;
timeFormat      general;
timePrecision   6;
runTimeModifiable true;

functions
{
   
    forcesBlades
{
    type          forces;

    libs          (forces);

    log           yes;

    patches       (aubes);
    rho           rhoInf;     // Indicates incompressible
    log           true;
    rhoInf        1.234;          // Redundant for incompressible

    CofR          (0 0 0);    // Rotation around centre line of propeller
    pitchAxis     (0 1 0);
}


    yPlusPump
    {
        type            yPlus;
        libs ("libfieldFunctionObjects.so");
        writeControl   timeStep;
        writeInterval  $saveIter;
        patches         ("fan wallinlet body");

     }
}
// ************************************************************************* //

fvSchemes

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  4.x                                   |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //



ddtSchemes
{
    default         steadyState;
}

divSchemes
{
    default         none;
    // Use second-order accurate convection
    // Bounded schemes for steady-state solution
    div(phi,U)      bounded Gauss linearUpwind grad(U);
    div((nuEff*dev2(T(grad(U))))) Gauss linear;
    div(div(phi,U)) Gauss linear;
    div(phi,k)      bounded Gauss upwind;
    div(phi,omega)  bounded Gauss upwind;
}

gradSchemes
{
    // Limit gradient to improve stability when bad cells encountered
    // (0 = no limiting; 1 = do not exceed surrounding cells)
    default         cellLimited Gauss linear 0.95;
    grad(p)         Gauss linear;
    grad(p_rgh)     Gauss linear;
    grad(k)         cellLimited Gauss linear 0.9;
    grad(omega)     cellLimited Gauss linear 0.9;
}

laplacianSchemes
{
    // Limited explicit correction to the surface normal gradient,
    // for stability in highly non-orthogonal cells.
    // (0 = uncorrected, fully implicit; 1 = full correction)
    default                     Gauss linear limited 0.6;
    laplacian(DomegaEff,omega)  Gauss linear limited 0.6;
    laplacian(DkEff,k)          Gauss linear limited 0.6;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    // Limited explicit correction to the surface normal gradient,
    // for stability in highly non-orthogonal cells.
    // (0 = uncorrected, fully implicit; 1 = full correction)
    default         limited 0.6;
}

wallDist
{
    method meshWave;
}


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

turbulenceProperties

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v1912                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "constant";
    object      turbulenceProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

//simulationType laminar;

simulationType RAS;

RAS
{
    RASModel        kOmegaSST;

    turbulence      on;

    printCoeffs     on;
}



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