[sjsivabharathy]

Hi all,
I'm using pisofoam to solve incompressible flow past multiple square cylinders at very low Reynolds number for Re < 150.
The maximum Courant number is 0.22.
I'm seeing oscillations in the time history of coefficients.
The flow seems ok.
Could someone suggest to me what should I do to aviod
such oscillations. I'm also showing below the controlDict, fvSchemes
and fvSolution file.
Thanks,
S Jawahar.

/*--------------------------------*- C++ -*----------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Version: 6
\\/ M anipulation |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application pisoFoam;

startFrom startTime;

startTime 186.790000000094494;

stopAt endTime;
//stopAt writeNow;

endTime 1000;

deltaT 0.001;

writeControl timeStep;

writeInterval 1000;

purgeWrite 0;

writeFormat ascii;

writePrecision 12;

writeCompression off;

timeFormat general;

timePrecision 6;

runTimeModifiable true;


fvSchemes:

/*--------------------------------*- C++ -*----------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Version: 6
\\/ M anipulation |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
default CrankNicolson 0.5;
ddt(phi) CrankNicolson 0.5;
}

gradSchemes
{
default Gauss linear;
}

divSchemes
{
default none;
div(phi,U) Gauss limitedLinearV 1;
div(phi,k) Gauss limitedLinear 1;
div(phi,epsilon) Gauss limitedLinear 1;
div(phi,omega) Gauss limitedLinear 1;
div(phi,R) Gauss limitedLinear 1;
div(R) Gauss linear;
div(phi,nuTilda) Gauss limitedLinear 1;
div((nuEff*dev2(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
default Gauss linear corrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

fvSolution:

/*--------------------------------*- C++ -*----------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Version: 6
\\/ M anipulation |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
p
{
solver GAMG;
tolerance 1e-06;
relTol 0.1;
smoother GaussSeidel;
}

pFinal
{
$p;
tolerance 1e-06;
relTol 0;
}

"(U|k|epsilon|omega|R|nuTilda)"
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-05;
relTol 0;
}
}

PISO
{
nCorrectors 3;
nNonOrthogonalCorrectors 0;
pRefCell 0;
pRefValue 0;
}