[mrishi]

Short version:
In OpenFOAM-6, I am trying to work on some mesh-to-mesh interpolation of fields (using meshToMesh.H -> imDirect). The turbulence variable return const tmp access to members, which lead to problem in interpolation. How should I go about it?


Details:

For the kEpsilon model, the turbulence variables k and epsilon, members of turbulenceModel (src/TurbulenceModels/turbulenceModels/RAS), are protected:

            volScalarField k_;
            volScalarField epsilon_;

These can be accessed through the functions:

//- Return the turbulence kinetic energy
         virtual tmp<volScalarField> k() const
        {
            return k_;
        }

        //- Return the turbulence kinetic energy dissipation rate
        virtual tmp<volScalarField> epsilon() const
        {
            return epsilon_;
        }

So, I try to access them for interpolation as so:

//source

    tmp<volScalarField> tksrc = turbulenceFluid[i].k();
    volScalarField& ksrc = tksrc.ref();
//tgt

    tmp<volScalarField> tktgt = turbulenceFluid[1-i].k();
    volScalarField& ktgt = tktgt.ref();

and similarly for epsilon.

Because of the use of tmp and const nature of access, appears to cause troubles when I try to interpolate the fields from one mesh to the other.

Attempt to acquire non-const reference to const object from a tmp<N4Foam14GeometricFieldIdNS_12fvPatchFieldENS_7volMeshEEE>tionThermoMoleFractions
sets
surfaces
)

My question is should I remove the const from the function, virtual tmp<volScalarField> const k() ? Or is their some reasoning behind putting it there that needs to be considered? Is there a correct way to implement access to these so that finally a volScalarField to volScalarField interpolation can be carried out by manipulating these datatypes correctly, without having to add additional non-const access function to the kEpsilon model? Would much appreciate feedback on this!!


PS: The idea of adding non-const access function comes, because I also did interpolation of volume fraction fields (src/transportModels/twoPhaseMixture model), but there the reference to alpha fields is returned via two methods, which allows manipulation via interpolation.

        //- Return the phase-fraction of phase 1
        const volScalarField& alpha1() const
        {
            return alpha1_;
        }

        //- Return the phase-fraction of phase 1
        volScalarField& alpha1()
        {
            return alpha1_;
        }

PS: the mapping operation is elementary, going as:

    mapF2C.mapSrcToTgt
    (
        epsilonsrc,
        plusEqOp<scalar> (),
        epsilontgt
    );

It seems to work correctly for other fields.

[Santiago]

Originally Posted by mrishi

Short version:
In OpenFOAM-6, I am trying to work on some mesh-to-mesh interpolation of fields (using meshToMesh.H -> imDirect). The turbulence variable return const tmp access to members, which lead to problem in interpolation. How should I go about it?


Details:

For the kEpsilon model, the turbulence variables k and epsilon, members of turbulenceModel (src/TurbulenceModels/turbulenceModels/RAS), are protected:

            volScalarField k_;
            volScalarField epsilon_;

These can be accessed through the functions:

//- Return the turbulence kinetic energy
         virtual tmp<volScalarField> k() const
        {
            return k_;
        }

        //- Return the turbulence kinetic energy dissipation rate
        virtual tmp<volScalarField> epsilon() const
        {
            return epsilon_;
        }

So, I try to access them for interpolation as so:

//source

    tmp<volScalarField> tksrc = turbulenceFluid[i].k();
    volScalarField& ksrc = tksrc.ref();
//tgt

    tmp<volScalarField> tktgt = turbulenceFluid[1-i].k();
    volScalarField& ktgt = tktgt.ref();

and similarly for epsilon.

Because of the use of tmp and const nature of access, appears to cause troubles when I try to interpolate the fields from one mesh to the other.

Attempt to acquire non-const reference to const object from a tmp<N4Foam14GeometricFieldIdNS_12fvPatchFieldENS_7volMeshEEE>tionThermoMoleFractions
sets
surfaces
)

My question is should I remove the const from the function, virtual tmp<volScalarField> const k() ? Or is their some reasoning behind putting it there that needs to be considered? Is there a correct way to implement access to these so that finally a volScalarField to volScalarField interpolation can be carried out by manipulating these datatypes correctly, without having to add additional non-const access function to the kEpsilon model? Would much appreciate feedback on this!!


PS: The idea of adding non-const access function comes, because I also did interpolation of volume fraction fields (src/transportModels/twoPhaseMixture model), but there the reference to alpha fields is returned via two methods, which allows manipulation via interpolation.

        //- Return the phase-fraction of phase 1
        const volScalarField& alpha1() const
        {
            return alpha1_;
        }

        //- Return the phase-fraction of phase 1
        volScalarField& alpha1()
        {
            return alpha1_;
        }

PS: the mapping operation is elementary, going as:

    mapF2C.mapSrcToTgt
    (
        epsilonsrc,
        plusEqOp<scalar> (),
        epsilontgt
    );

It seems to work correctly for other fields.

use const_cast<> to convert to non-const reference...

[mrishi]

Thanks!!! worked like a charm

[aot]

How did you solve the problem. I'm facing the same issue.
Could you please post the code snippet.