pEqn.H

{
    //-Calculate descretization coefficients based on the definition of Ueqn
    volScalarField rAU("rAU",1.0/UEqn.A());
    surfaceScalarField rAUf = fvc::interpolate(rAU);

    surfaceScalarField rhof = twoPhaseProperties.rhoMixF(scalar(0.5)*(alpha1.oldTime() + alpha1));

    //-Solve for the velocity based on the velocity terms described in UEqn.
    volVectorField HbyA("HbyA",U);
    HbyA = rAU*UEqn.H();

    /*
    // ddtPhiCorr //
    This term accounts for the divergence of the face velocity field by taking out the difference between the interpolated velocity and the flux
    */

    surfaceScalarField phiHbyA
    (
        "phiHbyA",
        (fvc::interpolate(HbyA) & mesh.Sf())
      + fvc::interpolate(rho*rAU)*fvc::ddtCorr(U,phi)
    );

    adjustPhi(phiHbyA,U,p_rgh);
    phi = phiHbyA;

    surfaceScalarField phig
    (
        (KSaG)*rAUf
    );

    phiHbyA += phig;

    //-Update the fixedFluxPressure BCs to ensure flux consistency
    // from https://www.cfd-online.com/Forums/openfoam-programming-development/187041-problem-compiling-solver-made-different-version-v2-0-v4-1-a.html
     constrainPressure(p_rgh, U, phiHbyA, rAUf);

    while (pimple.correctNonOrthogonal())
    {
        fvScalarMatrix p_rghEqn
        (
            fvm::laplacian(rAUf,p_rgh) == fvc::div(phi) 
        );

        p_rghEqn.setReference(pRefCell,getRefCellValue(p_rgh,pRefCell));
        p_rghEqn.solve(mesh.solver(p_rgh.select(pimple.finalInnerIter())));

        if (pimple.finalNonOrthogonalIter())
        {
            phi = phiHbyA - p_rghEqn.flux();

            U = HbyA + rAU*fvc::reconstruct((phig - p_rghEqn.flux())/rAUf);
            U.correctBoundaryConditions();
            fvOptions.correct(U);
        }
    }

    fvc::makeRelative(phi,U);

    #include "continuityErrs.H"

    p == p_rgh + rho*gh;

    if (p_rgh.needReference())
    {
        p += dimensionedScalar
        (
            "p",
            p.dimensions(),
            pRefValue - getRefCellValue(p,pRefCell)
        );
        p_rgh = p - rho*gh;
    }
}