Wrong radial velocity near the rotating wall

Su JH · November 2, 2022, 23:11

I am using the type rotatingWallVelocity to simulate taylor-couette flow. Strangely, the radial velocity of the rotating wall is equal to 0, while the cells close to the rotating wall, especially the first layer cells, show abnormal radial velocities. In order to observe this phenomenon more clearly, I simulated the case where the inner and outer walls have the same angular velocity. The inlet and outlet are set to be cyclic. The front patch and back patch are set to be empty.

The magnitude of velocity
image1.png

The radial velocity(ur)
image2.jpg

The radial velocity(ur) is obtained by codes following:
dimensionedVector zNormal("zNormal", dimless, vector(0.0, 0.0, 1.0));
volVectorField C = mesh.C();
volVectorField xy = (C - zNormal * (C & zNormal));
ur = U & xy / mag(xy);

0/U file

Code:

FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    location    "0";
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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


internalField   uniform (0 0 0);

boundaryField
{
    fixedWall
    {
        type            rotatingWallVelocity;
        origin          (0 0 0);
        axis            (0 0 1);
        omega           constant 2.72;
        value           uniform (0 0 0);
    }
    movingWall
    {
        type            rotatingWallVelocity;
        origin          (0 0 0);
        axis            (0 0 1);
        omega           constant 2.72;
	value           uniform (0 0 0);
    }
    patch1_inlet
    {
        type            cyclic;
    }
    patch1_outlet
    {
        type            cyclic;
    }
    patch2_periodic0
    {
        type            empty;
    }
    patch2_periodic1
    {
        type           empty;
    }
}

system/fvSchemes

Code:

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
    default         Euler;
}

gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
}

divSchemes
{
    default         none;
    div(phi,U)      Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear orthogonal;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         orthogonal;
}

system/fvSolution

Code:

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
    p
    {
        solver          PCG;
        preconditioner  DIC;
        tolerance       1e-06;
        relTol          0.05;
    }

    pFinal
    {
        $p;
        relTol          0;
    }

    U
    {
        solver          smoothSolver;
        smoother        symGaussSeidel;
        tolerance       1e-05;
        relTol          0;
    }
}

PISO
{
    nCorrectors     2;
    nNonOrthogonalCorrectors 1;
    pRefCell        0;
    pRefValue       0;
}

The run file is attached：rotatingWallVelocity_test.zip
OpenFOAM version : v2012

Beside, I also try to set the rotating velocity by codedFixedValue, finding the same results. So I think there is something wrong with the discrete format，but I can't check it out.

Code:

FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    location    "0";
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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


internalField   uniform (0 0 0);

boundaryField
{
    #includeEtc "caseDicts/setConstraintTypes"

    fixedWall
    {
        name    rotatingVelocity_out;
        type        codedFixedValue;
        code
        #{
            const vector axis(0, 0, 1);
            const scalar omega = 2.72;
            vectorField v(omega*this->patch().Cf() ^ axis);
            operator==(v);

        #};

       value           $internalField;
    }
    movingWall
    {
        name    rotatingVelocity_in;
        type        codedFixedValue;
        code
        #{
            const vector axis(0, 0, 1);
            const scalar omega = 2.72;
            vectorField v(omega*this->patch().Cf() ^ axis);
            operator==(v);

        #};

       value           $internalField;

    }
    patch1_inlet
    {
        type            cyclic;
    }
    patch1_outlet
    {
        type            cyclic;
    }
    patch2_periodic0
    {
        type            empty;
    }
    patch2_periodic1
    {
        type           empty;
    }
}

usrL · September 7, 2023, 15:56

Quote:

Originally Posted by Su JH

I am using the type rotatingWallVelocity to simulate taylor-couette flow. Strangely, the radial velocity of the rotating wall is equal to 0, while the cells close to the rotating wall, especially the first layer cells, show abnormal radial velocities. In order to observe this phenomenon more clearly, I simulated the case where the inner and outer walls have the same angular velocity. The inlet and outlet are set to be cyclic. The front patch and back patch are set to be empty.

The magnitude of velocity
Attachment 92200

The radial velocity(ur)
Attachment 92201

The radial velocity(ur) is obtained by codes following:
dimensionedVector zNormal("zNormal", dimless, vector(0.0, 0.0, 1.0));
volVectorField C = mesh.C();
volVectorField xy = (C - zNormal * (C & zNormal));
ur = U & xy / mag(xy);

0/U file

Code:

FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    location    "0";
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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


internalField   uniform (0 0 0);

boundaryField
{
    fixedWall
    {
        type            rotatingWallVelocity;
        origin          (0 0 0);
        axis            (0 0 1);
        omega           constant 2.72;
        value           uniform (0 0 0);
    }
    movingWall
    {
        type            rotatingWallVelocity;
        origin          (0 0 0);
        axis            (0 0 1);
        omega           constant 2.72;
	value           uniform (0 0 0);
    }
    patch1_inlet
    {
        type            cyclic;
    }
    patch1_outlet
    {
        type            cyclic;
    }
    patch2_periodic0
    {
        type            empty;
    }
    patch2_periodic1
    {
        type           empty;
    }
}

system/fvSchemes

Code:

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
    default         Euler;
}

gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
}

divSchemes
{
    default         none;
    div(phi,U)      Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear orthogonal;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         orthogonal;
}

system/fvSolution

Code:

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
    p
    {
        solver          PCG;
        preconditioner  DIC;
        tolerance       1e-06;
        relTol          0.05;
    }

    pFinal
    {
        $p;
        relTol          0;
    }

    U
    {
        solver          smoothSolver;
        smoother        symGaussSeidel;
        tolerance       1e-05;
        relTol          0;
    }
}

PISO
{
    nCorrectors     2;
    nNonOrthogonalCorrectors 1;
    pRefCell        0;
    pRefValue       0;
}

The run file is attached：Attachment 92202
OpenFOAM version : v2012

Beside, I also try to set the rotating velocity by codedFixedValue, finding the same results. So I think there is something wrong with the discrete format，but I can't check it out.

Code:

FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    location    "0";
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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


internalField   uniform (0 0 0);

boundaryField
{
    #includeEtc "caseDicts/setConstraintTypes"

    fixedWall
    {
        name    rotatingVelocity_out;
        type        codedFixedValue;
        code
        #{
            const vector axis(0, 0, 1);
            const scalar omega = 2.72;
            vectorField v(omega*this->patch().Cf() ^ axis);
            operator==(v);

        #};

       value           $internalField;
    }
    movingWall
    {
        name    rotatingVelocity_in;
        type        codedFixedValue;
        code
        #{
            const vector axis(0, 0, 1);
            const scalar omega = 2.72;
            vectorField v(omega*this->patch().Cf() ^ axis);
            operator==(v);

        #};

       value           $internalField;

    }
    patch1_inlet
    {
        type            cyclic;
    }
    patch1_outlet
    {
        type            cyclic;
    }
    patch2_periodic0
    {
        type            empty;
    }
    patch2_periodic1
    {
        type           empty;
    }
}

Hi,
I have the same problem. Did you solve it? If so, what was the problem?
Thanks in advance.

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