| pkr |
February 27, 2011 17:46 |
Some basic doubts on solvers
I have some basic doubts in the working of interFoam/dambreak case:
1. What difference does it make case if the following changes are made in controlDict:
Start time: 0
end time : 1
Changed to
start time: 0
end time: 0.25
I understand that it reduces the simulation time, but what happens to the quality/correctness of the results?
2. What equation is interFoam/dambreak actually solving? From the code in pEqn.H:
Code:
{
volScalarField rUA = 1.0/UEqn.A();
surfaceScalarField rUAf = fvc::interpolate(rUA);
U = rUA*UEqn.H();
surfaceScalarField phiU
(
"phiU",
(fvc::interpolate(U) & mesh.Sf())
+ fvc::ddtPhiCorr(rUA, rho, U, phi)
);
adjustPhi(phiU, U, p);
phi = phiU +
(
fvc::interpolate(interface.sigmaK())*fvc::snGrad(alpha1)*mesh.magSf()
+ fvc::interpolate(rho)*(g & mesh.Sf())
)*rUAf;
for(int nonOrth=0; nonOrth<=nNonOrthCorr; nonOrth++)
{
fvScalarMatrix pEqn
(
fvm::laplacian(rUAf, p) == fvc::div(phi)
);
pEqn.setReference(pRefCell, pRefValue);
if (corr == nCorr-1 && nonOrth == nNonOrthCorr)
{
pEqn.solve(mesh.solver(p.name() + "Final"));
}
else
{
pEqn.solve(mesh.solver(p.name()));
}
if (nonOrth == nNonOrthCorr)
{
phi -= pEqn.flux();
}
}
U += rUA*fvc::reconstruct((phi - phiU)/rUAf);
U.correctBoundaryConditions();
}
How do you interpret the mathematical version of equation being solved?
3. How does solving of some equation narrows down to PCG solver which solves the equation of the form Ax=b?
Thanks. |
