[mgao1]

Recently I am working on the denseParticleFoam, I have a question about the cloudSU term. It contains two part, cloudSU.source and cloudSU.diag, what do these two parts represent? Also, how to understand the following code to calculate cloudSU (clouds.SU)?

Foam::tmp<Foam::fvVectorMatrix> Foam:arcelCloudList::SU
(
volVectorField& U
) const
{
tmp<fvVectorMatrix> tSU(new fvVectorMatrix(U, dimMass*dimAcceleration));
forAll(*this, i)
{
tSU.ref() += operator[](i).SU(U);
}
return tSU;
}

Appreciate for any helps