rhoSimpleFoam convergence problem - bounding omega
 

Hi,
I am new to OpenFOAM.

I am trying to simulate flow through a valve with one inlet and one outlet. I want to look at the outlet mass flow rate and then calculate Cd value for the valve.

The problem is I am getting bounding omega error no matter what I change. The values are large negative numbers - four digit negative numbers.

I am using rhoSimpleFoam

Here are the files

k:
dimensions [0 2 -2 0 0 0 0];

internalField uniform 6.67;

boundaryField
{
egr_valve_inlet
{
type fixedValue;
value uniform 6.67;
}
egr_valve_outlet
{
type zeroGradient;
}
egr_valve_wall
{
type compressible::kqRWallFunction;
value uniform 6.67;
}
}

Omega:
dimensions [0 0 -1 0 0 0 0];

internalField uniform 645.659;

boundaryField
{
egr_valve_inlet
{
type fixedValue;
value uniform 645.659;
}
egr_valve_outlet
{
type zeroGradient;
}
egr_valve_wall
{
type compressible::omegaWallFunction;
value uniform 645.659;
}
}

U:
dimensions [0 1 -1 0 0 0 0];

internalField uniform (0 0 0);

boundaryField
{
egr_valve_inlet
{
type pressureInletVelocity;
value uniform (0 0 0);
}

egr_valve_outlet
{
type zeroGradient;
}

egr_valve_wall
{
type fixedValue;
value uniform (0 0 0);
}

}

p:
dimensions [1 -1 -2 0 0 0 0];

internalField uniform 95600;

boundaryField
{
egr_valve_inlet
{
type totalPressure;
U U;
phi phi;
rho rho;
psi none;
gamma 1.4;
p0 uniform 95600;
}

egr_valve_outlet
{
type fixedValue;
value uniform 94600;
}

egr_valve_wall
{
type zeroGradient;
}
}

T:
dimensions [0 0 0 1 0 0 0];

internalField uniform 298;

boundaryField
{
egr_valve_inlet
{
type fixedValue;
value uniform 487.924;
}

egr_valve_outlet
{
type zeroGradient;
}

egr_valve_wall
{
type fixedValue;
value uniform 298;
}
}

fvSchemes:
ddtSchemes
{
default steadyState;
}

gradSchemes
{
default Gauss linear;
}

divSchemes
{
div(phi,U) bounded Gauss upwind;
div((muEff*dev2(T(grad(U))))) Gauss linear;
div(phi,e) bounded Gauss upwind;
div(phi,omega) bounded Gauss upwind;
div(phi,k) bounded Gauss upwind;
div(phi,Ekp) bounded Gauss upwind;
}

laplacianSchemes
{
laplacian(muEff,U) Gauss linear corrected;
laplacian(alphaEff,e) Gauss linear corrected;
laplacian((rho*(1|A(U))),p) Gauss linear corrected;
laplacian(DomegaEff,omega) Gauss linear corrected;
laplacian(DkEff,k) Gauss linear corrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

fluxRequired
{
default no;
p ;
}

fvSolution:
solvers
{
p
{
solver GAMG;
tolerance 1e-08;
relTol 0.05;
smoother GaussSeidel;
cacheAgglomeration off;
nCellsInCoarsestLevel 20;
agglomerator faceAreaPair;
mergeLevels 1;
}

U
{
solver smoothSolver;
smoother GaussSeidel;
nSweeps 2;
tolerance 1e-06;
relTol 0.1;
}

e
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-06;
relTol 0.1;
}

"(k|omega)"
{
$U;
tolerance 1e-07;
relTol 0.1;
}
}

SIMPLE
{
nNonOrthogonalCorrectors 0;
rhoMin rhoMin [ 1 -3 0 0 0 ] 0.5;
rhoMax rhoMax [ 1 -3 0 0 0 ] 1.5;

residualControl
{
p 1e-4;
U 1e-4;
e 1e-4;

// possibly check turbulence fields
"(k|omega)" 1e-4;
}
}

relaxationFactors
{
fields
{
p 0.3;
rho 0.05;
}
equations
{
U 0.7;
"(k|omega)" 0.7;
e 0.5;
}
}

I change tolerances and solvers and i get different answers everytime. The temperature plots are very weird and even if the solution says it is converged, the feilds are changing as i change the time step.

Please help me solve this problem. :confused::confused:

Hello,
I would suggest trying simpler solution and then U should go for complex problem as you are a beginner.

I think you should go for a mesh convergence study and please have some reference to see whether your solution is correct or not.


LOL just noticed that this was asked in 2013.