Hi Hrvoje, Sorry to not rep
 

Hi Hrvoje,

Sorry to not replying you for the last time (about a_N coefficients. I re-read your thesys, but it stil not ok for me), but in emmergency, I want to know where I'm wrong in the implementation of a Stokes solver:
I begin with the simpleFOam.C file: so I just removed the div(phi,U) and changed some "minus" by "plus", according to he discretisation of Navier-Stokes, explained in your thesys.
(in my simulation, I put turbulence OFF)
****************************
tmp<fvvectormatrix> UEqn
(turbulence->divR(U));
UEqn().relax();
solve(UEqn() == -fvc::grad(p));
p.boundaryField().updateCoeffs();
volScalarField AU = UEqn().A();
U = UEqn().H()/AU;
UEqn.clear();
phi = fvc::interpolate(U) & mesh.Sf();
adjustPhi(phi, U, p);

for (int nonOrth=0; nonOrth<=nNonOrthCorr; nonOrth++)
{
fvScalarMatrix pEqn
(
// I put a "minus" here, because now: Up=[H(U)+grad(p)]/ap, so the discretisation of div(U)=0 gives me the equation of pressure below:
fvm::laplacian(1.0/AU, p) == -fvc::div(phi));
pEqn.setReference(pRefCell, pRefValue); pEqn.solve();
if (nonOrth == nNonOrthCorr)
{
// "+=" instead of "-=" because F = S.Uf = S.[H(U)/ap]f + S.[grad(p)/ap]f
phi += pEqn.flux();
}
}

# include "continuityErrs.H"

p.relax();
// "+=" instead of "-=" because Up=[H(U)+grad(p)]/ap
U += fvc::grad(p)/AU;
U.correctBoundaryConditions();
}

********************
the end of the program is the same.
It seems so easy, but I can't get by myself.
I just need your patience to tell me where I'm wrong.

Thanks in advance,

Lam

just take a little look please
 

just take a little look please http://www.cfd-online.com/OpenFOAM_D...part/happy.gif

? You have messed up the signs
 

? You have messed up the signs: just delete the convection terms and use a symmetric solver for the momentum equation.

I haven't got time to go through this in detail, but it should really be as simple as that.

Hrv

Hi Hrvoje, Thanks to reply
 

Hi Hrvoje,

Thanks to reply me.
Ok, I'm going to delete the convection term...
even if I don't understand why the signs are wrong.
Hope that you will explain me when you get more time.

Cheers,

Lam