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BuoyantFoam and total pressure bc problem is a bug

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Old   January 23, 2008, 05:22
Default Can anybody just comment this
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Rosario Russo
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Can anybody just comment this please?

http://www.cfd-online.com/cgi-bin/Op...9416#POST19416

Thanks.

Rosario.
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Old   January 27, 2008, 15:22
Default Hello, I'm writing here a s
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Rosario Russo
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Hello,

I'm writing here a short summary and an update of the issue.

I discovered that using totalPressure bc in buoyantFoam solver is not possible. The problem is that when pd is constructed via

volScalarField pd
(
IOobject
(
"pd",
runTime.timeName(),
mesh
),
p - rho*gh - pRef,
p.boundaryField().types()
);


the boundaryField types are not completely copied from p: i.e. the name for U phi and gamma are set to "undefined" and so the bc is made unusable.

I have seen that this is due the a precise constructor of totalPressureFvPatchScalarField.C, so I think there must be a reason why Devolopers did so.

By the way I realized that using this bc in buoyantFoam, choosing the isentropic relation to relate p and p0, would be misleading since the bc is used for the pd field which actually is a relative pressure: the isentropic relation would be wrong in this case.

I'm not sure whether I'm right or whether I misunderstood something: any comments to sustain or deny what I said would be much appreciated.

Thanks.

Rosario.
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Old   January 27, 2008, 15:58
Default The easiest way around such in
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The easiest way around such initialization problems is to change the constructor to pd to a "read" constructor which would then allow you to specify all the information necessary for totalPressure and other complex BCs and then set the initial field values to p - rho*gh - pRef using an assignment statement. Also to apply a totalPressure BC to pd you will need to take into account the fact that it is pd rather than p in the formulation of the BC.

Henry
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Old   January 28, 2008, 05:20
Default Ok. It is more or less what I
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Rosario Russo
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Ok. It is more or less what I did.

Thank you very much.

Rosario.
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