Originally Posted by ata (Post 338603)

Hi
Are you sure you complied the solver after the commenting, correctly, and did not use converged data as initial data?

Originally Posted by ata (Post 338603)

Hi
Are you sure you complied the solver after the commenting, correctly, and did not use converged data as initial data?

Originally Posted by mechy (Post 338443)

Hello All
I could not found the role of term "solve(UEqn == -fvc::grad(p));"
in icoFoam pisoFoam and ...
when I have deactivated this term (insert // befor it) the answer did not changed.
it is worthwhile to notice that if this term calculate algebraic equation for U and find the new U but this new U is not used in the following of the program and term
U = rAU*UEqn.H();
replaced the new value in variable U

Best Regards
Yasser

Originally Posted by Bernhard (Post 338712)

If you look closely to the pisoFoam solver, you will see that this term is only executed when the momentumPredictor flag is set to true. Please have a look at Hrvoje Jasaks thesis in paragraph 3.8 where most of this is explained. Does ignoring this line have an effect on the convergence rate (check your log files)

Originally Posted by nandiganavishal (Post 339452)

Dear Foamers,

I would like to know which algorithm the following code represents. Is it PISO or SIMPLE algorithm. Kindly let me know and also the reason for the same.

for (int corr = 0; corr < nCorr; corr++)
{
tmp<fvVectorMatrix> UEqn
(
fvm::ddt(U)
+ fvm::div(phi, U)
- fvm::laplacian(nu, U)

);

UEqn().relax();

eqnResidualU = solve
(
UEqn() == -fvc::grad(p)
).initialResidual();

maxResidual_U = max(eqnResidualU, maxResidual_U);

p.boundaryField().updateCoeffs();
volScalarField rUA = 1.0/UEqn().A();
U = rUA*UEqn().H();
UEqn.clear();
phi = fvc::interpolate(U) & mesh.Sf();
adjustPhi(phi, U, p);

p.storePrevIter();

// Non-orthogonal pressure corrector loop
for (int nonOrth=0; nonOrth<=nNonOrthCorr; nonOrth++)
{
fvScalarMatrix pEqn
(
fvm::laplacian(rUA, p) == fvc::div(phi)
);

pEqn.setReference(pRefCell, pRefValue);
pEqn.solve();

if (nonOrth == nNonOrthCorr)
{
phi -= pEqn.flux();
}
}

p.relax();

U -= rUA*fvc::grad(p);
U.correctBoundaryConditions();
Info << eqnResidualU << endl;
}

Thanks

Regards

Vishal