[Yang16024]

Hi all,

I am working with OpenFoam version 9. And I am currently studying the cavitatingFoam solver. But there is a phiGradp term in the pEqn.H file which really confused me.


---------------------------pEqn.H-----------------------------------
...

surfaceScalarField rhof("rhof", fvc::interpolate(rho));

volScalarField rAU(1.0/UEqn.A());
surfaceScalarField rhorAUf("rhorAUf", fvc::interpolate(rho*rAU));
volVectorField HbyA(constrainHbyA(rAU*UEqn.H(), U, p));

phi = fvc::flux(HbyA) + rhorAUf*fvc::ddtCorr(U, phi, Uf);
fvc::makeRelative(phi, U);

surfaceScalarField phiGradp(rhorAUf*mesh.magSf()*fvc::snGrad(p));

phi -= phiGradp/rhof;

volScalarField rho0(rho - psi*p);

while (pimple.correctNonOrthogonal())
{
fvScalarMatrix pEqn
(
fvc::ddt(rho)
+ psi*correction(fvm::ddt(p))
+ fvc::div(phi, rho)
+ fvc::div(phiGradp)
- fvm::laplacian(rhorAUf, p)
);

...
--------------------------------------------------------------------------

So my questions are:

-What does this term phiGradp mean and Where does it come from ?
-Why the phi term has to minus the phiGradp/rhof before the pressure-correction loop and then plus it back ( fvc::div(phiGradp) ) in the loop ?

It would be really nice if you can help me to understand this.

Thanks