[AB08]

Hi,, am very new to OpenFoam....... can sm1 please tell me

Q1) What is the exact function of fvOptions(U) in the UEqn.H file of simpleFoam? (I assumed that it gave the guessed value of the velocity(U) field (am I right) and if so from where does the initial guess come) ??



tmp<fvVectorMatrix> UEqn
(
fvm::div(phi, U)
+ turbulence->divDevReff(U)
==
fvOptions(U)
);

UEqn().relax();

fvOptions.constrain(UEqn());

solve(UEqn() == -fvc::grad(p));

fvOptions.correct(U);


Q2) What is the function of adjustPhi(phiHbyA, U, p); in the pEqn.H of simpleFoam?



{
volScalarField rAU(1.0/UEqn().A());
volVectorField HbyA("HbyA", U);
HbyA = rAU*UEqn().H();
UEqn.clear();

surfaceScalarField phiHbyA("phiHbyA", fvc::interpolate(HbyA) & mesh.Sf());
adjustPhi(phiHbyA, U, p);

fvOptions.relativeFlux(phiHbyA);

// Non-orthogonal pressure corrector loop
while (simple.correctNonOrthogonal())
{
fvScalarMatrix pEqn
(
fvm::laplacian(rAU, p) == fvc::div(phiHbyA)
);

pEqn.setReference(pRefCell, pRefValue);

pEqn.solve();

if (simple.finalNonOrthogonalIter())
{
phi = phiHbyA - pEqn.flux();
}
}

#include "continuityErrs.H"

// Explicitly relax pressure for momentum corrector
p.relax();

// Momentum corrector
U = HbyA - rAU*fvc::grad(p);
U.correctBoundaryConditions();
fvOptions.correct(U);
}