[linyanx]

Dear Foams,

I'm having a hard time to understand the proper way to express the governing equations. I am currently creating one solver for solving the elliptic equation based on solver ‘LaplacianFoam’.
I think everything is well compiled so far except one problem remaining for the proper expression of the governing equation. I am not well understood the process of the matrix equations' manipulation. Hence, the format of the field is not defined correctly.
I am trying to write the equation in the following way.

fvm::div(sigma , fvc::grad(Phi_E))
- fvm::div(sigma * A)

But the compiler will complain as follow:

error: no matching function for call to ‘div(Foam::volScalarField&, Foam::tmp<Foam::GeometricField<Foam::Vector<dou
ble>, Foam::fvPatchField, Foam::volMesh> >)’
fvm::div(sigma , fvc::grad(Phi_E))

Or can you please read the ellipticFoam.C file to see the equation expression part and give me some comment about the right way to express the equation?
I’ve also attached the governing equation attached for your reference.

Any suggestion is kindly appreciated!

Best,
Antelope

[linyanx]

The thing goes well. I am trying to derivate my governing equation into a separate form.


solve
(
fvm::laplacian(Phi_E)
+ fvm::laplacian(sigma, Phi_E)
- A * fvc::grad(sigma)
- sigma * fvc::div(A)
)


The first two terms work. However, when I tried to write the last two terms in the equation above. The system complains again and give me a lot of note about the matrix manipulation.

ellipticFoam.C:35:23: note: ‘Foam::tmp<Foam::fvMatrix<double> >’ is not derived from ‘const Foam::GeometricField<TypeR, PatchField, Geo
Mesh>’
- A * fvc::grad(sigma)
^
In file included from /usr/local/openfoam/OpenFOAM-4.1/src/OpenFOAM/lnInclude/GeometricField.C:1306:0,
from /usr/local/openfoam/OpenFOAM-4.1/src/OpenFOAM/lnInclude/GeometricField.H:651,
from /usr/local/openfoam/OpenFOAM-4.1/src/OpenFOAM/lnInclude/GeometricScalarField.H:38,
from /usr/local/openfoam/OpenFOAM-4.1/src/OpenFOAM/lnInclude/GeometricFields.H:34,
from /usr/local/openfoam/OpenFOAM-4.1/src/finiteVolume/lnInclude/volFields.H:37,
from /usr/local/openfoam/OpenFOAM-4.1/src/finiteVolume/lnInclude/surfaceInterpolationScheme.C:27,
from /usr/local/openfoam/OpenFOAM-4.1/src/finiteVolume/lnInclude/surfaceInterpolationScheme.H:304,
from /usr/local/openfoam/OpenFOAM-4.1/src/finiteVolume/lnInclude/surfaceInterpolate.H:41,
from /usr/local/openfoam/OpenFOAM-4.1/src/finiteVolume/lnInclude/fvc.H:39,
from /usr/local/openfoam/OpenFOAM-4.1/src/finiteVolume/lnInclude/fvCFD.H:8,
from ellipticFoam.C:1:
/usr/local/openfoam/OpenFOAM-4.1/src/OpenFOAM/lnInclude/GeometricFieldFunctions.C:657:1: note: template<class Type1, class Type2, templat
e<class> class PatchField, class GeoMesh> Foam::tmp<Foam::GeometricField<typename Foam::typeOfSum<Type1, Type2>::type, PatchField, GeoMes
h> > Foam:perator-(const Foam::GeometricField<TypeR, PatchField, GeoMesh>&, const Foam::tmp<Foam::GeometricField<Type1, PatchField, Geo
Mesh> >&)
operator op \


It seems like I did something wrong with the matrix manipulation.