[NilsTilton]

Dear OpenFoam community,

As part of my learning OpenFoam, I am trying to solve a 2D Poisson equation of the form \nabla^2 T = sin(x)*sin(y) using the laplacianFoam solver. I have already experimented extensively with solving the simpler Laplace equation \nabla^2 T=0. I consulted the header file for laplacianFoam, and it states that it solves a PDE of the form

fvm::ddt(T) - fvm:: laplacian(DT , T) == fvModels.source(T)

I then searched for what little documentation I could find on fvModels, and I decided to prescribe the source term using the codedFvModel. From the header file for that, my understanding is I need to add a file named "fvModels" in the constant subdirectory. I wrote the file shown below, and added it to the constant directory. However, from the output, it seems the file is not being read, and the source term is not being implemented. When I run laplacianFoam I see the text "No finite volume options present" appear at one point. I believe this has to do with the fact source terms used to be applied using fvOptions. Does anyone have any suggestions? Thanks!

FoamFile
{
version 2.0;
format ascii;
class dictionary;
object fvModels;
}

PoissonSource
{
type coded;
selectionMode all;
field T;

codeAddSup
#{
Pout<< "**codeAddSup**" << endl;

// get cell volume
const scalarField& V = mesh().V();

// access eon.source()
scalarField& f = eqn.source();

// get the x and y coordinates of the cell centroids
scalarField x(mesh_.C()&vector(1,0,0));
scalarField y(mesh_.C()&vector(0,1,0));

// compute the source term
f += Foam::sin(x)*Foam::sin(y)*V;

#};


}

[NilsTilton]

Just as an additional update, I searched the tutorials folder using the "find" command for any file named fvModels as well as any instance of the text "fvModels," and it returned zero instances.

[NilsTilton]

And as another update: I am able to get the source term if I use the following fvOptions file in the constant folder. I am confused, because I did find other posts where people successfully used fvModels to add source terms to laplacianFoam. Anyone have any ideas? Is there something wrong with my OpenFOAM install?

PoissonSource
{

type scalarCodedSource;
name Tsource;
selectionMode all;

scalarCodedSourceCoeffs
{

selectionMode all;
fields (T);

codeInclude
#{
#};

codeCorrect
#{
Pout<<"**codeCorrect**" << endl;
#};

codeAddSup
#{

const scalarField& V = mesh_.V();
scalarField& TSource = eqn.source();
scalarField x(mesh_.C()&vector(1,0,0));
scalarField y(mesh_.C()&vector(0,1,0));

TSource += Foam::sin(x)*Foam::sin(y)*V;

#};

codeConstrain
#{
Pout<<"**codeConstrain**" << endl;
#};
}

}