[farzadmech]

Dear friends
I was working with reactingParcelFoam and I realized that the main equation for species transport has dimension probem. The main equation from YEqn.H is;

            fvScalarMatrix YEqn
            (
                fvm::ddt(rho, Yi)
              + mvConvection->fvmDiv(phi, Yi)
              - fvm::laplacian(turbulence->muEff(), Yi)
              ==
                parcels.SYi(i, Yi)
              + fvOptions(rho, Yi)
              + combustion->R(Yi)
              + surfaceFilm.Srho(i)
            );

fvm::ddt(rho, Yi) dimension is Mass/Volume/Time and the parcels.SYi(i, Yi) dimension is Mass/Time. In order to be confidant about dimension of the parcels.SYi(i, Yi), I have copied the SYi function from ReactingCloudI.H as below;

 tmp<fvScalarMatrix> tfvm(new fvScalarMatrix(Yi, dimMass/dimTime));

or;

template<class CloudType>
inline Foam::tmp<Foam::fvScalarMatrix> Foam::ReactingCloud<CloudType>::SYi
(
    const label i,
    volScalarField& Yi
) const
{
    if (this->solution().coupled())
    {
        if (this->solution().semiImplicit("Yi"))
        {
            tmp<volScalarField> trhoTrans
            (
                new volScalarField
                (
                    IOobject
                    (
                        this->name() + ":rhoTrans",
                        this->db().time().timeName(),
                        this->db(),
                        IOobject::NO_READ,
                        IOobject::NO_WRITE,
                        false
                    ),
                    this->mesh(),
                    dimensionedScalar("zero", dimMass/dimTime/dimVolume, 0.0)
                )
            );

            volScalarField& sourceField = trhoTrans.ref();

            sourceField.primitiveFieldRef() =
                rhoTrans_[i]/(this->db().time().deltaTValue()*this->mesh().V());

            const dimensionedScalar Yismall("Yismall", dimless, small);

            return
                fvm::Sp(neg(sourceField)*sourceField/(Yi + Yismall), Yi)
              + pos0(sourceField)*sourceField;
        }
        else  // if (this->solution().semiImplicit("Yi"))

        {
            tmp<fvScalarMatrix> tfvm(new fvScalarMatrix(Yi, dimMass/dimTime));
            fvScalarMatrix& fvm = tfvm.ref();

            fvm.source() = -rhoTrans_[i]/this->db().time().deltaTValue();

            return tfvm;
        }
    }

    return tmp<fvScalarMatrix>(new fvScalarMatrix(Yi, dimMass/dimTime));
}

Do you have any suggestion why it does not give dimension error?


Thanks,
Farzad

[H.Tofighian]

Are you try to multiply the source term by a arbitrary dimension? maybe it is not sensitive to dimension!

[farzadmech]

Thanks for your answer. I checked what you said. source term is completely sensitive to dimension, and whenever I change it, I got error so basically this is not the case.

Originally Posted by H.Tofighian

Are you try to multiply the source term by a arbitrary dimension? maybe it is not sensitive to dimension!

[farzadmech]

Dear friends
I have found another problem in the KinematicCloudI.H which I will be very thankful if you know the answer;

if (this->solution().coupled())
    {
        if (this->solution().semiImplicit("Yi"))
        {
            tmp<volScalarField> trhoTrans
            (
                new volScalarField
                (
                    IOobject
                    (
                        this->name() + ":rhoTrans",
                        this->db().time().timeName(),
                        this->db(),
                        IOobject::NO_READ,
                        IOobject::NO_WRITE,
                        false
                    ),
                    this->mesh(),
                    dimensionedScalar("zero", dimMass/dimTime/dimVolume, 0.0)
                )
            );

            volScalarField& sourceField = trhoTrans.ref();

            sourceField.primitiveFieldRef() =
                rhoTrans_[i]/(this->db().time().deltaTValue()*this->mesh().V());

            const dimensionedScalar Yismall("Yismall", dimless, small);

            return
                fvm::Sp(neg(sourceField)*sourceField/(Yi + Yismall), Yi)
              + pos0(sourceField)*sourceField;
        }
        else   //         if (this->solution().semiImplicit("Yi"))
        {
            tmp<fvScalarMatrix> tfvm(new fvScalarMatrix(Yi, dimMass/dimTime));
            fvScalarMatrix& fvm = tfvm.ref();

            fvm.source() = -rhoTrans_[i]/this->db().time().deltaTValue();

            return tfvm;
        }
    }

My question is that why the dimension of "if" is dimMass/dimTime/dimVolume and dimension of "else" is dimMass/dimTime.

Thanks,
Farzad