[12ohan]

Hello,

I'm currently doing a project using pimpleFoam which consists of two inlets and one outlet. The two inlets had been assigned almost sinusoidal flow rates with a period of 1 that range from 0 to 5 seconds. My problem is that my output values like the velocities, pressure, courant number, etc. all rapidly increase to huge values (over 1e+40) after the first second. I'm not sure why this is the case. I have tried using small deltaT values like 0.0001 and even used adjustTimeStep which made deltaT very small but the courant number increased even quicker and simulation stop at around 3.5 seconds. Below are my current files that I modified.

My p file:
{
Wall
{
type zeroGradient;
}

Inlet1
{
type zeroGradient;
}

Inlet2
{
type zeroGradient;
}

Outlet
{
type fixedValue;
value uniform 0;
}
}


My U file:
{
Wall
{
type noSlip;
}

Inlet1
{
type flowRateInletVelocity;
volumetricFlowRate tableFile;
volumetricFlowRateCoeffs
{
outOfBounds repeat;
file "Inlet1.csv";
}
extrapolateProfile false;
value uniform (0 0 0);
}


Inlet2
{
type flowRateInletVelocity;
volumetricFlowRate tableFile;
volumetricFlowRateCoeffs
{
outOfBounds repeat;
file "Inlet2.csv";
}
extrapolateProfile false;
value uniform (0 0 0);
}


Outlet
{
type zeroGradient;
}
}

My controlDict file:
application pimpleFoam;

startFrom startTime;

stopAt endTime;

startTime 0;

endTime 5;

deltaT 0.005;

writeControl adjustableRunTime;

writeInterval 0.02;

purgeWrite 0;

writeFormat ascii;

writePrecision 6;

writeCompression off;

timeFormat general;

timePrecision 6;

runTimeModifiable true;

adjustTimeStep no;

maxCo 1.0;

maxDeltaT 0.1;
// ************************************************** *********************** //

functions
{
fieldAverage1
{
type fieldAverage;
libs ("libfieldFunctionObjects.so");
executeControl timeStep;
writeControl writeTime;
timeStart 0;
timeEnd 5;

fields
(
U
{
mean on;
prime2Mean on;
base time;
}
p
{
mean on;
prime2Mean on;
base time;
}
);
}

}

functions
{
forces
{
type forces;

libs ("libforces.so");

writeControl timeStep;
timeInterval 0.02;

log yes;

patches ("Wall");
rho rhoInf;
log true;
rhoInf 1;

CofR (0 0 0);
pitchAxis (0 0 0);
p p;
U U;
}
}

My fvSchemes file:
ddtSchemes
{
default Euler;
}

gradSchemes
{
default Gauss linear;
}

divSchemes
{
default none;
div(phi,U) Gauss LUST grad(U);
div(phi,k) Gauss limitedLinear 1;
div((nuEff*dev2(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
default Gauss linear corrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

My fvSolution file:
solvers
{
p
{
solver PCG;
preconditioner FDIC;
tolerance 1e-06;
relTol 0;
//maxIter 100;
}

pFinal
{
$p;
relTol 0;
}

U
{
solver PBiCGStab;
preconditioner DILU;
tolerance 1e-05;
relTol 0;
//maxIter 100;
}

UFinal
{
$U;
relTol 0;
}
}

PIMPLE
{
momentumPredictor off;
nOuterCorrectors 1;
nCorrectors 2;
nNonOrthogonalCorrectors 0;
pRefCell 0;
pRefValue 0;
}

relaxationFactors
{
equations
{
".*" 1;
}
}

It would be very nice if someone can help me out here.
Thanks.

[12ohan]

Hi, if someone can help me. I am new to this field and still really struggling.

Thanks.