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how I can increase the accuracy of flow pressure ?

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Old   September 20, 2013, 16:40
Default how I can increase the accuracy of flow pressure ?
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mechy is on a distinguished road
i all
I have simulated flow around a cylinder by OF and FLUENT
In both software, I use a high quality and fine structure mesh which lead to y+<5 over walls and use Kw-sst model

also the setting for OF and FLUENT is as follow

FLUENT BCs:
inlet ========> velocity inlet U=7m/sec k=.2 omega=170
outlet=======> pressure outlet
FLUENT settigs
solver =============> PISO
residual=1e-5


In OF I have used pimpleFoam and setting are as follow

any help will be appreciated


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

internalField   uniform 0.2;

boundaryField
{
    outlet
    {
        type            zeroGradient;
    }
    inlet
    {
        type             fixedValue;
        value           uniform .2;
    }
    circle
    {
        type            kLowReWallFunction;
        value           uniform 1e-6;
    }
    frontAndBackPlanes
    {
        type            empty;
    }
Code:
    object      omega;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [ 0 0 -1 0 0 0 0 ];

internalField   uniform 170;

boundaryField
{
    outlet
    {
        type zeroGradient;
    }
    inlet
    {
        type    fixedValue;
        value           uniform 170;
    }
    circle
    {
        type            omegaWallFunction;
        value           uniform 1e-6;
    }
Code:
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [ 0 1 -1 0 0 0 0 ];

internalField   uniform ( 0 0 0 );

boundaryField
{
    
    }
    circle
    {
        type            fixedValue;
        value           uniform ( 0 0 0 );
    }
    wall
    {
        type            fixedValue;
        value           uniform ( 0 0 0 );
    }
    inlet
    {
        type            fixedValue;
        value           uniform ( 7. 0 0 );
    }
    outlet
    {
        type            zeroGradient;
Code:
    object      nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField   uniform 0;

boundaryField
{
    wallup
    {
        type            nutUSpaldingWallFunction;
        value           uniform 0;
    }
    wallp
    {
        type            nutUSpaldingWallFunction;
        value           uniform 0;
    }
    outlet
    {
        type            calculated;
        value           uniform 0;
    }
    inlet
    {
        type            calculated;
        value           uniform 0;
    }
    circle
    {
        type            nutUSpaldingWallFunction;
        value           uniform 0;
 }
Code:
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
    default Euler;
}

gradSchemes
{
    default           Gauss linear ;
}

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

laplacianSchemes
{
    default         Gauss linear corrected;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         corrected;
}

fluxRequired
{
    default         no;
//    pcorr           ;
    p;
}
Code:
solvers
{
    p
    {
        solver           GAMG;
        tolerance        1e-5;
        relTol           0;
        smoother         GaussSeidel;
        nPreSweeps       1;
        nPostSweeps      2;
        cacheAgglomeration true;
        directSolveCoarsest true;
        agglomerator     faceAreaPair;
        nCellsInCoarsestLevel 100;
        mergeLevels      1;
        minIter          1;
    }
    pFinal
    {
        solver           GAMG;
        tolerance        1e-9;
        relTol           0;
        smoother         GaussSeidel;
        nPreSweeps       1;
        nPostSweeps      2;
        cacheAgglomeration true;
        agglomerator     faceAreaPair;
        nCellsInCoarsestLevel 100;
        mergeLevels      1;
        minIter          1;
    }

    "(U|k|omega)"
    {
        solver           smoothSolver;
        smoother         GaussSeidel;
        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    4;
    nCorrectors         2;
    nNonOrthogonalCorrectors 3;

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