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Solution is NOT APPROPRIATE WHEN COMPARED TO CFX

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Old   February 18, 2014, 00:54
Default Solution is NOT APPROPRIATE WHEN COMPARED TO CFX
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adarsh tiwari
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Hi all,

I am trying to do some simulations in turbulent modelling using OpenFOAM and also comparing the results with CFX.

the velocity in the OF's results is nearly zero due to no pressure drop, while in CFX, i am satisfied with the velocity range of 65 m/s with some pressure drop.

The solvers I have used for trial are

1) rhoLTSPimpleFoam
2) rhoSimpleFoam
3) simpleFoam

[the 'P' file] [/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.2.2 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField uniform 0.956e5;

boundaryField
{
HOUSING
{
type zeroGradient;
}
VALVE
{
type zeroGradient;
}

INLET
{
type zeroGradient;
}
OUTLET
{
type fixedValue;
value $internalField;
}
}
]


[The T file][/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.2.2 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object T;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 0 0 1 0 0 0];

internalField uniform 487.94;

boundaryField
{

HOUSING
{
type fixedValue;
value uniform 298;
}
VALVE
{
type fixedValue;
value uniform 298;
}
INLET
{
type fixedValue;
value uniform 487.94;
}
OUTLET
{
type zeroGradient; //inletOutlet;
// value $internalField;
// inletValue $internalField;
}
}]

[the U file] [/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.2.2 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField uniform (0 0 0);

boundaryField
{
HOUSING
{
type fixedValue;
value uniform (0 0 0);
}
VALVE
{
type fixedValue;
value uniform (0 0 0);
}
INLET
{
type pressureInletVelocity; //flowRateInletVelocity;
// massFlowRate constant 0.00085;
value uniform (0 0 0);
}
OUTLET
{
type flowRateInletVelocity; //inletOutlet; //fluxCorrectedVelocity;
massFlowRate constant 0.00085;
value uniform (0 0 0);
//inletValue uniform (0 0 0);
}
}

// ************************************************** *********************** //]

Except some flow pattern variations all the results are nearly same for all the solvers.

I have to solve it ASAP, else my instructor will kick my a$$

Thanks in Advance,
ragards,
Adarsh Tiwari
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Old   April 2, 2014, 02:29
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adarsh tiwari
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nothing at all ....????
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Old   April 2, 2014, 03:59
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Vojtech Betak
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You have mess in boundary conditions. For velocity you have to prescribe mass flow on inlet and zeroGradient/inletOutlet on outlet. For temperature is better to use adiabatic wall zeroGradient on the wall
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Old   April 2, 2014, 14:45
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Kyle Mooney
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How to give enough info to get help
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Old   April 10, 2014, 02:25
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adarsh tiwari
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Thanks betakv and kmooney,

It solved the issue.

Best Regards,
Adarsh Tiwari
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