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Strange pressure/velocity fields using buoyantPimpleFoam

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Old   August 25, 2020, 12:29
Default Strange pressure/velocity fields using buoyantPimpleFoam
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Liv Pontes
Join Date: Nov 2019
Posts: 1
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Hello Foamer,

I am studying the influences of the external flow of exhaustion fan in a helical condenser using bouyantPimpleFoam. My problem consists:

- The domain is a "wind tunnel”;
- The fan is rotating with 162 rad/s;
- The velocity in the inlet is 1 m/s;
- The condenser has a variation of temperature, but its internal flow is not analysed.

The problem is my results seems strange, because p_rgh and U are not uniform as it should be and p has some kind of stain, as it can be seen in the pictures for the time 0.35s.

Picture_p.JPG

Picture_U.JPG

Picture_prgh.JPG

These are my checkMesh, fvSolution, fvSchemes and boundary conditions for p, p_rgh and U.

checkMesh:

Create time

Checking geometry...
Overall domain bounding box (-0.6624 -0.552 -0.552) (1.26835 0.552 0.552)
Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
Mesh has 3 solution (non-empty) directions (1 1 1)
Boundary openness (8.72236e-17 -1.89034e-16 1.21992e-16) OK.
Max cell openness = 3.28732e-16 OK.
Max aspect ratio = 7.35925 OK.
Minimum face area = 7.81001e-07. Maximum face area = 0.0149429. Face area magnitudes OK.
Min volume = 3.39861e-10. Max volume = 0.000531389. Total volume = 2.35281. Cell volumes OK.
Mesh non-orthogonality Max: 69.7345 average: 17.2367
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 1.4638 OK.
Coupled point location match (average 0) OK.

Mesh OK.

End

fvSolution:

ddtSchemes
{
default Euler;
}

gradSchemes
{
default Gauss linear;
grad(U) cellLimited Gauss linear 1;
}

divSchemes
{
default none;
div(phi,U) bounded Gauss linearUpwindV grad(U);
div(phi,k) bounded Gauss upwind;
div(phi,omega) bounded Gauss upwind;

div(((rho*nuEff)*dev2(T(grad(U))))) Gauss linear;

div(meshPhi,p) Gauss linear;

div(phi,h) Gauss upwind;
div(phi,e) Gauss upwind;
div(phi,R) Gauss upwind;
div(phi,K) Gauss linear;
div(phi,Ekp) Gauss linear;
div(R) Gauss linear;
}

laplacianSchemes
{
default Gauss linear corrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

wallDist
{
method meshWave;
}

fvSolution:

solvers
{
"rho.*"
{
solver PCG;
preconditioner DIC;
tolerance 0;
relTol 0;
}


p_rgh
{
solver PCG;
preconditioner DIC;
tolerance 1e-8;
relTol 0.01;
}

p_rghFinal
{
$p_rgh;
relTol 0;
}

"pcorr.*"
{
solver GAMG;
smoother DICGaussSeidel;
cacheAgglomeration no;
maxIter 50;

tolerance 1e-2;
relTol 0;

}
"(U|h|e|k|omega|R)"
{
solver PBiCGStab;
preconditioner DILU;
tolerance 1e-6;
relTol 0.1;
}

"(U|h|e|k|omega|R)Final"
{
$U;
relTol 0;
}
}

PIMPLE
{
momentumPredictor yes;
nOuterCorrectors 1;
nCorrectors 2;
nNonOrthogonalCorrectors 0;
}

U:

Uinlet (1 0 0);

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

internalField uniform (1 0 0);

boundaryField
{
inlet
{
type fixedValue;
value uniform $Uinlet;
}

outlet
{
type pressureInletOutletVelocity;
value uniform $Uinlet;
}

wall
{
type noSlip;
}

fan
{
type movingWallVelocity;
value uniform (0 0 0);
}

"wall_cond_.*"
{
type noSlip;
}

ami_2
{
type cyclicAMI;
value $internalField;
}

ami_1
{
type cyclicAMI;
value $internalField;
}
}

p:

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

internalField uniform 1e5;

boundaryField
{
outlet
{
type calculated;
value $internalField;
}

inlet
{
type calculated;
value $internalField;
}

wall
{
type calculated;
value $internalField;
}

fan
{
type calculated;
value $internalField;
}
"wall_cond_.*"
{
type calculated;
value $internalField;
}
ami_2
{

type cyclicAMI;
value $internalField;

}
ami_1
{
type cyclicAMI;
value $internalField;
}
}

p_rgh:

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

internalField uniform 0;

boundaryField
{
outlet
{
type fixedValue;
value uniform 0;
}

inlet
{
type fixedFluxPressure;
value uniform 0;
}

wall
{
type fixedFluxPressure;
value uniform 0;
}
fan
{
type fixedFluxPressure;
value uniform 0;
}
"wall_cond_.*"
{
type fixedFluxPressure;
value uniform 0;
}
ami_2
{

type cyclicAMI;
value $internalField;

}
ami_1
{
type cyclicAMI;
value $internalField;
}

}

I don't know why this is happening and I hope that someone could help me.
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Old   August 25, 2020, 23:13
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  #2
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Ardalan
Join Date: Jul 2012
Location: Atlanta, USA
Posts: 77
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can you share your case?
That is hard to tell like this?
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