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-   -   Low pressure result in low velocity region for RNG-ke? (http://www.cfd-online.com/Forums/openfoam-solving/90597-low-pressure-result-low-velocity-region-rng-ke.html)

Gabbee90 July 14, 2011 20:48

Low pressure result in low velocity region for RNG-ke?
 
Hi,
I have ran a SimpleFOAM RAS -RNG- K-e model of a ball vale at a small % opening position, as an axi symmetric model.
At the moment I have using PCG with a preconditioner of GAMG for the pressure calculations in fv schemes:
p
{
solver PCG;
preconditioner
{
preconditioner GAMG;
tolerance 1e-7;
relTol 0.1;
smoother GaussSeidel;
nPreSweeps 0;
nPostSweeps 2;
cacheAgglomeration on;
agglomerator faceAreaPair;
nCellsInCoarsestLevel 10;
mergeLevels 1;
};
tolerance 1e-06;
relTol 0.01;
maxIter 100;
and

solver PBiCG;
preconditioner DILU;
tolerance 1e-05;
relTol 0.1;

for K U and epsilon

My relaxation factors are:
relaxationFactors
{
p 0.7;
U 0.2;
k 0.5;
epsilon 0.5;

My result has an extremely low pressure region in area of low velocity. I feel as though this is not correct and am not sure what to do to optimize the model and get a better result. I have tried adjusting delta T and write time in controldict. I can get pressure residuals to converge but still have the same result
Any Ideas?


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