[NewtonianGuy]

Hello! I am having an issue with simpleFoam (and am new to openFoam). In fact, the solution doesnt want to converge, specially the pressure. My case used the tutorial incompressible/simpleFoam/windaroundbuilding, and even this tutorial doesnt converge (didnt change anything...). If anyone can help or guide me I would really appreciate it!

case : flow around a structure (turbulence k-epsilon)

Below are my nschemes/fvsolution/controlDict files and 0 files. There's also the residuals plot (attached).

Thanks!

fschemes

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2006                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
    default         steadyState;
}

gradSchemes
{
    default         Gauss linear;

    limited         cellLimited Gauss linear 1;
    grad(U)         $limited;
    grad(k)         $limited;
    grad(epsilon)     $limited;
}

divSchemes
{
    default         none;

    div(phi,U)      bounded Gauss linearUpwind limited;

    turbulence      bounded Gauss limitedLinear 1;
    div(phi,k)      $turbulence;
    div(phi,epsilon) $turbulence;

    div((nuEff*dev2(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear corrected;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         corrected;
}

wallDist
{
    method meshWave;
}

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

fvsolution

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2006                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
    p
    {
        solver          GAMG;
        smoother        GaussSeidel;
        tolerance       1e-6;
        relTol          0.1;
    }

    "(U|k|omega|epsilon)"
    {
        solver          smoothSolver;
        smoother        symGaussSeidel;
        tolerance       1e-6;
        relTol          0.1;
    }
}

SIMPLE
{
    residualControl
    {
        p               1e-4;
        U               1e-4;
        "(k|omega|epsilon)" 1e-4;
    }
    nNonOrthogonalCorrectors 0;
    pRefCell        0;
    pRefValue       0;

}

potentialFlow
{
    nNonOrthogonalCorrectors 10;
}

relaxationFactors
{
    fields
    {
        p               0.3;
    }
    equations
    {
        U               0.7;
        "(k|omega|epsilon).*" 0.7;
    }
}

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

controlDict

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2006                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application     simpleFoam;

startFrom       startTime;

startTime       0;

stopAt          endTime;

endTime         2000;

deltaT          1;

writeControl    timeStep;

writeInterval   100;

purgeWrite      0;

writeFormat     ascii;

writePrecision  6;

writeCompression off;

timeFormat      general;

timePrecision   6;

runTimeModifiable true;

functions
{
    //#includeFunc streamlines
}

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

U

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2006                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

//Uinlet          (10 0 0);

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    "inlet_bot|inlet_top"
    {
        /*type            fixedValue;
        value           uniform $Uinlet;*/
		type       fixedProfile;
        profile    csvFile;

        profileCoeffs
        {
            nHeaderLine         0;          // Number of header lines
            refColumn           0;          // Reference column index
            componentColumns    (1 2 3);    // Component column indices
            separator           ",";        // Optional (defaults to ",")
            mergeSeparators     no;         // Merge multiple separators
            file                "$FOAM_CASE/0/Uprofile3.csv";  // name of csv data file
            outOfBounds         clamp;      // Optional out-of-bounds handling
            interpolationScheme linear;     // Optional interpolation scheme
        }
        direction        (0 1 0);
        origin           0;
    }

    outlet
    {
        type            pressureInletOutletVelocity;
        value           uniform (0 0 0);
    }

    wall
    {
        type            noSlip;
    }

    #includeEtc "caseDicts/setConstraintTypes"
}

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

P

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2006                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -2 0 0 0 0];

internalField   uniform 0;

boundaryField
{
    "inlet_bot|inlet_top"
    {
        type            zeroGradient;
    }

    outlet
    {
        type            totalPressure;
        p0              uniform 0;
    }

    wall
    {
        type            zeroGradient;
    }

    #includeEtc "caseDicts/setConstraintTypes"
}

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

k

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2006                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      k;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

kInlet          0.015;   // approx k = 1.5*(I*U)^2 ; I = 0.1

dimensions      [0 2 -2 0 0 0 0];

internalField   uniform $kInlet;

boundaryField
{
    "inlet_bot|inlet_top"
    {
        type            fixedValue;
        value           uniform $kInlet;
    }

    outlet
    {
        type            inletOutlet;
        inletValue      uniform $kInlet;
        value           uniform $kInlet;
    }

    wall
    {
        type            kqRWallFunction;
        value           uniform $kInlet;
    }

    #includeEtc "caseDicts/setConstraintTypes"
}

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

epsilon

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2006                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      epsilon;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

epsilonInlet  2.755675961e-03; // Cmu^0.75 * k^1.5 / L ; L =10

dimensions      [0 2 -3 0 0 0 0];

internalField   uniform $epsilonInlet;

boundaryField
{
    "inlet_bot|inlet_top"
    {
        type            fixedValue;
        value           uniform $epsilonInlet;
    }

    outlet
    {
        type            inletOutlet;
        inletValue      uniform $epsilonInlet;
        value           uniform $epsilonInlet;
    }

    wall
    {
        type            epsilonWallFunction;
        value           uniform $epsilonInlet;
    }

    #includeEtc "caseDicts/setConstraintTypes"
}

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

nut

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2006                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -1 0 0 0 0];

internalField   uniform 0;

boundaryField
{
    "inlet_bot|inlet_top"
    {
        type            calculated;
        value           uniform 0;
    }

    outlet
    {
        type            calculated;
        value           uniform 0;
    }

    wall
    {
        type            nutkWallFunction;
        value           uniform 0;
    }

    #includeEtc "caseDicts/setConstraintTypes"
}

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

[petros]

Hi,

The residuals seem that have reached convergence as they do not change any more. But that's only an indicator for a converged solution. Although, 0.1 might seem large, there other factors in that tutorial which may have an influence, e.g. the mesh, which is rather coarse. To understand convergence, you should monitor flow variables, mass flows etc. as well.

Best,
Petros