[linch]

Hello FOAM_Community,
how can I obtain a diffusive mass flux resulting from solving a species equation:

    fvScalarMatrix xN2Eqn
    (
             fvm::ddt(rho*alpha1, xN2)
           + fvm::div(rhoPhi, xN2)
           - fvm::laplacian(DN2f, xN2)
           ==
             rhoN2Su
    );
    xN2Eqn.solve();

what I need is a surfaceScalarField jN2f.
xN2Eqn.flux() would return the overall flux. fvc::laplacian(DN2f, xN2) would probably return a volScalarField which equals to the cell flux divergence, right? So what I thought about is something like:

volScalarField jN2 = fvc::laplacian(DN2f, xN2);
surfaceScalarField jN2f = fvc::interpolate(jN2);

Is this way completely wrong? Even if it works, I suspect I don't necessarily get the same fluxes like those, resulting from the solution of the xN2Eqn. I think there must be a better way.

regards,

[linch]

The reason for doing this is: mass diffusion causes enthalpy transport. That's why I need diffusive mass fluxes from the species equations.