[JyoCFD]

Hi foamers,

I was looking at incompressibleDriftFlux.C to understand how the scalar equation for alpha is solved.


void Foam::solvers::incompressibleDriftFlux:rePredict or()
{
VoFSolver:rePredictor();
alphaPredictor();

// Apply the diffusion term separately to allow implicit solution
// and boundedness of the explicit advection
{
fvScalarMatrix alpha1Eqn
(
fvm::ddt(alpha1) - fvc::ddt(alpha1)
- fvm::laplacian(momentumTransport->nut(), alpha1)
);

alpha1Eqn.solve(alpha1.name() + "Diffusion");

alphaPhi1 += alpha1Eqn.flux();
alpha2 = 1.0 - alpha1;

Info<< "Phase-1 volume fraction = "
<< alpha1.weightedAverage(mesh.Vsc()).value()
<< " Min(" << alpha1.name() << ") = " << min(alpha1).value()
<< " Max(" << alpha1.name() << ") = " << max(alpha1).value()
<< endl;
}

mixture.correct();

const dimensionedScalar& rho1 = mixture.rho1();
const dimensionedScalar& rho2 = mixture.rho2();

// Calculate the mass-flux from the accumulated alphaPhi1
rhoPhi = (alphaPhi1*(rho1 - rho2) + phi*rho2);

relativeVelocity->correct();

if (pimple.predictTransport())
{
momentumTransport->predict();
}
}

Could someone help me understand where " alpha1Eqn.solve(alpha1.name() + "Diffusion");" is detailed in the code.

The equation solved is detailed in this literature: https://doi.org/10.1016/j.apm.2019.08.008