Add soure terms to the momentum equation

Shibi · April 26, 2021, 16:02

Hello to all,

I am becoming myself familiar with the method of manufactured solutions and would like to add a source term on the u and v components of the momentum equation with fvOptions in pimpleFoam.

The sources have the following form:

$S_u = \pi \left(- 1.6 \left(2.0 \sin{\left(0.8 \pi x \right)} - 0.6\right) \cos{\left(0.8 \pi y \right)} + 1.28 \pi \sin{\left(0.8 \pi y \right)}\right)$

$S_v = - \pi \left(1.6 \left(2.0 \sin{\left(0.8 \pi y \right)} + 1.0\right) \cos{\left(0.8 \pi x \right)} + 1.28 \pi \sin{\left(0.8 \pi x \right)}\right)$

Currently, I have:

Code:

MomentumSource
{
    type            vectorCodedSource;
    selectionMode   all;
    fields          (U);

    // Name of the coded source
    name            sourceTime;

    codeInclude
    #{

    #};

    codeCorrect
    #{

    #};
       

    codeConstrain
    #{

    #};
    codeAddSup
    #{

        // Info: Include sources into equation

        // Gets the cell volumes of the mesh
        const scalarField& V = mesh_.V();

        // Gets the vector containing cell centers position of the mesh
        const volVectorField& cellCenter = mesh().C();

        // Gets the equation source term
        vectorField& USource = eqn.source();

        const scalar pi = constant::mathematical::pi;

        // Loop over the source term
        forAll(USource, cellI)
        {    
            // Gets the x component of the current cell
            const scalar x = cellCenter[cellI].component(0);

            // Gets the y component of the current cell
            const scalar y = cellCenter[cellI].component(1);

            // U source term
             const scalar S_u = pi*(-1.6*(2.0*Foam::sin(0.8*pi*x) - 0.6)*Foam::cos(0.8*pi*y) + 1.28*pi*Foam::sin(0.8*pi*y))

             // V source term
           const scalar S_v = -pi*(1.6*(2.0*Foam::sin(0.8*pi*y) + 1.0)*Foam::cos(0.8*pi*x) + 1.28*pi*Foam::sin(0.8*pi*x))

            USource[cellI][0]=-V[cellI]*(S_u);
            USource[cellI][1]=-V[cellI]*(S_v);
            USource[cellI][2]= 0.0;
        };
        
    #};
}

Can anyone confirm this implementation?

Does anyone have experience with this in OpenFOAM? Any advices?

Mahmoud Abbaszadeh · June 23, 2022, 16:27

Quote:

Originally Posted by Shibi

Hello to all,

I am becoming myself familiar with the method of manufactured solutions and would like to add a source term on the u and v components of the momentum equation with fvOptions in pimpleFoam.

The sources have the following form:

$S_u = \pi \left(- 1.6 \left(2.0 \sin{\left(0.8 \pi x \right)} - 0.6\right) \cos{\left(0.8 \pi y \right)} + 1.28 \pi \sin{\left(0.8 \pi y \right)}\right)$

$S_v = - \pi \left(1.6 \left(2.0 \sin{\left(0.8 \pi y \right)} + 1.0\right) \cos{\left(0.8 \pi x \right)} + 1.28 \pi \sin{\left(0.8 \pi x \right)}\right)$

Currently, I have:

Code:

MomentumSource
{
    type            vectorCodedSource;
    selectionMode   all;
    fields          (U);

    // Name of the coded source
    name            sourceTime;

    codeInclude
    #{

    #};

    codeCorrect
    #{

    #};
       

    codeConstrain
    #{

    #};
    codeAddSup
    #{

        // Info: Include sources into equation

        // Gets the cell volumes of the mesh
        const scalarField& V = mesh_.V();

        // Gets the vector containing cell centers position of the mesh
        const volVectorField& cellCenter = mesh().C();

        // Gets the equation source term
        vectorField& USource = eqn.source();

        const scalar pi = constant::mathematical::pi;

        // Loop over the source term
        forAll(USource, cellI)
        {    
            // Gets the x component of the current cell
            const scalar x = cellCenter[cellI].component(0);

            // Gets the y component of the current cell
            const scalar y = cellCenter[cellI].component(1);

            // U source term
             const scalar S_u = pi*(-1.6*(2.0*Foam::sin(0.8*pi*x) - 0.6)*Foam::cos(0.8*pi*y) + 1.28*pi*Foam::sin(0.8*pi*y))

             // V source term
           const scalar S_v = -pi*(1.6*(2.0*Foam::sin(0.8*pi*y) + 1.0)*Foam::cos(0.8*pi*x) + 1.28*pi*Foam::sin(0.8*pi*x))

            USource[cellI][0]=-V[cellI]*(S_u);
            USource[cellI][1]=-V[cellI]*(S_v);
            USource[cellI][2]= 0.0;
        };
        
    #};
}

Can anyone confirm this implementation?

Does anyone have experience with this in OpenFOAM? Any advices?

Hi, did that work for you?

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