[medmast]

Hi all,
I am trying to implement a new boundary condition that reads Internal fields U, P, and temperature from external solver and write these fields from OpenFOAM in a file for external solver.
to this end, i use the "externalCoupledMixedFvPatchField" boundary patch and i edit it.
i try the following code to write data in OpenFOAM fields:

 const volScalarField& Pressure= this->db().objectRegistry::lookupObject<volScalarField>("p");
   const volVectorField& Velocity= this->db().objectRegistry::lookupObject<volVectorField>("U");
   const volScalarField& Temperature= this->db().objectRegistry::lookupObject<volScalarField>("T");


    forAll(this->patch(), facei)
     {
             // define mesh on patch
             const fvMesh& mesh = this->patch().boundaryMesh().mesh();


                   // cell related to current face
                 label celli =this->patch().faceCells()[facei];

                  // define opposite face to patch face//
                 label oppfacei =mesh.cells()[celli].opposingFaceLabel
                                      (facei+this->patch().patch().start(),mesh.faces());
                 // define neighbour cell centre cellCentreN
                 vector cellCentreN = mesh.cellCentres()[mesh.owner()[oppfacei]];

                 // define patch cell centre cellCentre0
                 vector cellCentreO = mesh.cellCentres()[mesh.neighbour()[oppfacei]];


                 // cell lable of  cell
                 label CellP =mesh.findCell(cellCentreO);

 Pressure.internalField()[CellP] = "new value";


         }

Here I have error that Pressure field constant it, and when I try to define it as volScalarField, I can't define it with objectRegistry.
has anyone the idea, how i can change internal fields U,P and T within a boundary patch?
Thank you
iman

[alexeym]

Hi,

You have const_cast and ref.

[medmast]

Originally Posted by alexeym

Hi,

You have const_cast and ref.

yes exactly, now my question is how can i define the internal variable not constant , or how can i change the internalfields at patch (not facevalues)

[alexeym]

Well, now my question is what error happens if you add const_cast to your lookups and use ref instead of internalField to set value? And, please, this time post compiler output.

[medmast]

Originally Posted by alexeym

Well, now my question is what error happens if you add const_cast to your lookups and use ref instead of internalField to set value? And, please, this time post compiler output.

actually no error but i can just read the internalfields, i want to change them too, because they are defined const_cast , they are not changeable
i'll post it at freiday, i don't have them right now.
thank you very much

[alexeym]

Yes, internalField is read-only, ref is not (also you can use const_cast on internalField if you REALLY want).

[medmast]

Originally Posted by alexeym

Yes, internalField is read-only, ref is not (also you can use const_cast on internalField if you REALLY want).

thank you for your solution.
how i understood, i must define internal fields as "const_cast " , then they are not read-only anymore?
and could you please a little explain about "ref"?

[alexeym]

You CAN not that you MUST. Post #2 contains a link to ref documentation, not quite get what additional explanations do you need.

You use const_cast to remove const from field references you look up using objectRegistry, then you use ref method to access writable lists for modification of the fields.