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set Min and Max values for pressure in pimpleFoam

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Old   September 2, 2013, 17:57
Default set Min and Max values for pressure in pimpleFoam
  #1
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Hi all

in my problem the velocities are calculated correctly but pressure is not.
I use pimpleFoam and I want to limit the pressure

I add bellow statment in fvSolution/PIMPLE

pMin pMin [ 0 2 -2 0 0 0 0 ] -150;
pMax pMax [ 0 2 -2 0 0 0 0 ] 150;

but it not work

any help will be appreciated
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Old   September 3, 2013, 00:13
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Nima Samkhaniani
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Hello

did you change your solver at all!? then those lines would not reflect anything to solver
besides as you use incopressible solver i dont gauss its a good idea to limit the pressure which will be effect on continuity too and it may impair divergence issue
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Old   September 3, 2013, 01:05
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Hi Nima


I have added the setting of my test case as follow:

more information:
I use my icoFsiFoam solver which used pimpleFoam for solve fluid.
the results is good until time=0.1205 with maxCor=.6 ( deltaT ~1e-5)
at the next state (Time = 0.1205+deltaT) the velocity is calculated correctly, but pressure not.
I check the original pimpleFoam solver to solve fluid only, but the pressure is diverged again. I have attached its contours.



fvSchemes

HTML Code:
ddtSchemes
{
    default Euler;
}

gradSchemes
{
    default           Gauss linear ;//cellMDLimited leastSquares 1;//extendedLeastSquares 1;
//    grad(p)         leastSquares ;
//    grad(U)         leastSquares ;
}

divSchemes
{
    default         none;
    div(phi,U)      Gauss limitedLinearV 1;//Gauss linearUpwindV grad(U);//
    div(phi,k)      Gauss upwind;//limitedLinear 1;
    div(phi,omega)  Gauss upwind;//limitedLinear 1;
    div((nuEff*dev(T(grad(U))))) Gauss linear;
     div((nuEff*dev(grad(U).T())))  Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear corrected;//Gauss linear limited 0.5;//
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         corrected;
}

fluxRequired
{
    default         no;
    pcorr           ;
    p;
}

// ************************************************************************* //

fvSolutions


HTML Code:
solvers
{
    p
    {
        solver           GAMG;
        tolerance        1e-4;
        relTol           0;
        smoother         GaussSeidel;
        nPreSweeps       1;
        nPostSweeps      2;
        cacheAgglomeration true;
        directSolveCoarsest true;
        agglomerator     faceAreaPair;
        nCellsInCoarsestLevel 40;
        mergeLevels      1;
        minIter          1;
    }
    pFinal
    {
        solver           GAMG;
        tolerance        1e-8;
        relTol           0;
        smoother         GaussSeidel;
        nPreSweeps       1;
        nPostSweeps      2;
        cacheAgglomeration true;
        agglomerator     faceAreaPair;
        nCellsInCoarsestLevel 40;
        mergeLevels      1;
        minIter          1;
    }

    "(U|k|omega)"
    {
        solver          PBiCG;
        preconditioner  DILU;

        tolerance        1e-5;
        relTol           0;
        nSweeps          1;     
        minIter          1;
    }
    "(UFinal|kFinal|omegaFinal)"
    {

        solver           smoothSolver;
        smoother         GaussSeidel;
        tolerance        1e-6;
        relTol           0.0;
        nSweeps          1;   
        minIter          1;
    }
}

PIMPLE
{
    nOuterCorrectors    3;
    nCorrectors         2;
    nNonOrthogonalCorrectors 3;

    pRefCell            0;
    pRefValue           0;
//    momentumPredictor yes;
    ddtPhiCorr no;
    correctPhi no;

}

relaxationFactors
{
    fields
    {
        p               0.3;
    }
    equations
    {
        U               0.7;
        k               0.7;
        omega           0.7;
    }
}
cache
{
    grad(U);
}

// ************************************************************************* //
Attached Images
File Type: jpg P_1205OK.jpg (21.0 KB, 14 views)
File Type: jpg P_120501_notOK.jpg (17.0 KB, 11 views)
File Type: jpg U_120501_OK.jpg (17.8 KB, 16 views)
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Old   September 3, 2013, 02:24
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Bernhard
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Bounding pressure is certainly not the way to go. Check your velocity in a few more time steps, and you will probably see something weird there as well. In other words, your solution is diverging, please check the residuals of the equations from the log file. It might be wise to study the origin of the pressure issue, which might well be related to the FSI part.
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