[randolph]

Hi everyone,

I am interested in simulating a scalar transport within the primary phase (i.e., water) in the interFoam.

I follow the approach of phaseScalarTransport (https://github.com/OpenFOAM/OpenFOAM...larTransport.H) and successfully added a scalar transport to the primary phase with MULES compressed flux (i.e., alphaPhiUn).

    fvScalarMatrix YEqn
    (
          fvm::ddt(Y)
        + fvm::div(alphaPhiUn, Y)
        - fvm::laplacian(Deff, Y)
        ==
        alpha1*fvOptions(Y)
    );

    YEqn.relax();
    fvOptions.constrain(YEqn);
    YEqn.solve();

The code runs well and as expected the scalar is transported only within the water phase. When the water surface arises, the scalar will arise too. However, when the water surface falls, the part of the scalar will "stuck" above the surface (see attachment). I would like to have scalar fall as the water falls. Could you please shed some light on this issue?

Thanks,
Rdf