[fnohpat]

Dear FOAMers,

If someone could please advise me on the following: I am implementing buoyancy force with the Boussinesq approximation in the momentum equations as a source term in the "fvModels" file.

buoyancyBoussinesqForce
{
type coded;
select all;

field U;

codeInclude
#{
#};

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

codeAddRhoSup
#{
Pout<< "**codeAddRhoSup**" << endl;
const scalar T0 = 293.5;
const scalar rho0 = 1.20329;
const scalar beta = 0.003407155;

const volScalarField& T = mesh().lookupObject<volScalarField>("T"); //T field

//double buoyancy = -0.001;
double buoyancy= -9.81*rho0*(1.0-beta*(T-T0));
//Pout<< "T = "<<T<< endl;

vectorField& USource = eqn.source();
USource += vector(0, buoyancy, 0); //,
#};

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


But, I have the following error:

error: cannot convert ‘Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> >’ to ‘double’ in initialization
make: *** [/opt/openfoam11/wmake/rules/General/transform:26: Make/linux64GccDPInt32Opt/codedFvModelTemplate.o] Error 1

The error is in: double buoyancy= -9.81*rho0*(1.0-beta*(T-T0));

What is the correct variable type for buoyancy?

I'm solving natural convection in a square cavity with OpenFOAM 11. For verification purposes, I want to solve it using the Boussinesq approximation.

Thansk a lot
Felipe Noh