[SandilyaCFD]

Hello
I am trying to solve two scalar transport equations using OpenFoam.

:
:
{
//Equation 1
solve
(
fvm::laplacian(DT,V)
);

U = -constant * fvc::grad(V);

surfaceScalarField phiU
(
"phiU",
(fvc::interpolate(U) & mesh.Sf())

);


//Scalar Equation 2

solve
(
fvm::ddt(R)
+ fvm::div(phiU,R)
- fvm::laplacian(DR,R)
)

}


How do I calculate the flux term. The term U above is the convective velocity for the species R. But I need to calculate the flux.

I use the surface scalar field option but the scalar R does not experience convection when I run.

Thank you.