codedFIxedValue, writing only to Z-Component of an Inletpatch

fanta · May 12, 2018, 10:20

Hi,

i am working on a codedFixedValue Boundarycondition and i am stuck.
At the inlet i want to read the calculated rho from the field and correct the mass flow rate with the continuity equation. It starts with a rho read from the file rho.
Here ist my U file:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.1.x                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     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            codedFixedValue;
    value        uniform (0 0 0.011449586); //5kg/h in +Z-Direction respectiv to the inlet;
    redirectType    rho_corrected;
    code
    #{
        const fvPatch& boundaryPatch = this->patch(); 
        vectorField& U = *this;
             const vectorField& Cf = boundaryPatch.Cf();
        scalar patchArea = gSum(boundaryPatch.magSf());
         const volScalarField& rhop = this->db().lookupObject<volScalarField>("rho");
        const scalar m_dot = 5.0/3600.0; // 5 kg/h Massflowrate
        volScalarField v = (m_dot/(rhop*patchArea)); //Continuity Equation
//        tmp<vectorField> n = this->patch().nf();
        fixedValueFvPatchVectorField myPatch(*this);
        forAll(this->patch().Cf(),i)
        {
            myPatch[i]=vector(0,0,v);
//            myPatch[i]=vector(0,0,0.011449586);
        }
        operator==(myPatch);
    #};
    }
    outlet
    {
        type            zeroGradient;
    }

    wall
    {
        type            noSlip;
    }
    defaultFaces
    {
    type         fixedValue;
    value        uniform (0 0 0);
    }
}

Can someone help me? It doesn't run because of this line:
myPatch[i]=vector(0,0,v);

in the For loop. Seems i cannot apply v as a component to a vector. How do i do this? v is from the type volScalarField, vector is a vector (of which type of components?).

Taataa · May 12, 2018, 11:28

Because you've defined v as a field then you've used it as a scalar!

Either directly calculate v in the loop using rhop[i] or use v[i].

fanta · May 12, 2018, 12:55

Thanks for the hint, this is the code:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.1.x                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     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            codedFixedValue;
    value        uniform (0 0 0.011449586); //5kg/h in +Z-Direction respectiv to the inlet;
    redirectType    rho_corrected;
    code
    #{
        const fvPatch& boundaryPatch = this->patch(); 
        vectorField& U = *this;
             const vectorField& Cf = boundaryPatch.Cf();
        scalar patchArea = gSum(boundaryPatch.magSf());
         const volScalarField& rhop = this->db().lookupObject<volScalarField>("rho");
        const scalar m_dot = 5.0/3600.0; // 5 kg/h Massflowrate
//        scalar v = (m_dot/(rhop[2]*patchArea));
        fixedValueFvPatchVectorField myPatch(*this);
        forAll(this->patch().Cf(),i)
        {
            myPatch[i]=vector(0,0, (m_dot/(rhop[2]*patchArea)));
        }
        operator==(myPatch);
    #};
    }
    outlet
    {
        type            zeroGradient;
    }

    wall
    {
        type            noSlip;
    }
    defaultFaces
    {
    type         fixedValue;
    value        uniform (0 0 0);
    }
}

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

Zhiheng Wang · May 24, 2018, 10:28

Quote:

Originally Posted by fanta

Thanks for the hint, this is the code:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.1.x                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     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            codedFixedValue;
    value        uniform (0 0 0.011449586); //5kg/h in +Z-Direction respectiv to the inlet;
    redirectType    rho_corrected;
    code
    #{
        const fvPatch& boundaryPatch = this->patch(); 
        vectorField& U = *this;
             const vectorField& Cf = boundaryPatch.Cf();
        scalar patchArea = gSum(boundaryPatch.magSf());
         const volScalarField& rhop = this->db().lookupObject<volScalarField>("rho");
        const scalar m_dot = 5.0/3600.0; // 5 kg/h Massflowrate
//        scalar v = (m_dot/(rhop[2]*patchArea));
        fixedValueFvPatchVectorField myPatch(*this);
        forAll(this->patch().Cf(),i)
        {
            myPatch[i]=vector(0,0, (m_dot/(rhop[2]*patchArea)));
        }
        operator==(myPatch);
    #};
    }
    outlet
    {
        type            zeroGradient;
    }

    wall
    {
        type            noSlip;
    }
    defaultFaces
    {
    type         fixedValue;
    value        uniform (0 0 0);
    }
}

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

Excellent work thanks

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May 12, 2018, 11:28		#2
Taataa Senior Member Taher Chegini Join Date: Nov 2014 Location: Houston, Texas Posts: 125 Rep Power: 12	Because you've defined v as a field then you've used it as a scalar! Either directly calculate v in the loop using rhop[i] or use v[i].