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incompressible, The exact meaning of P in case/0/p ?

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Old   December 1, 2009, 23:27
Default incompressible, The exact meaning of P in case/0/p ?
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Jiang
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Dear all:
For simpleFoam solver, what is the exzct meaning of P in case/0/P file ?
It is refference value or the actual value ?
for initial field and outlet condition , we should set 0 or 101325/rho ?
Because I saw many imcompressible case set it to 0, but I set 101325/rho .
Thank you very much.
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Old   December 2, 2009, 00:44
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Masashi Ohbuchi
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There is no meaning for the value of p in incompressible flow. Only the gradient term of p is appeared in Navier-Stokes eq.
You can start both from p=0 or p=101324/rho, then simulated result may be translate by constant value.
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Old   December 2, 2009, 01:09
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Quote:
Originally Posted by Ohbuchi View Post
There is no meaning for the value of p in incompressible flow. Only the gradient term of p is appeared in Navier-Stokes eq.
You can start both from p=0 or p=101324/rho, then simulated result may be translate by constant value.
Thanks Ohbuchi,
I am l little understand, I saw the solver of simpleFoam ,in creatfields,H

# include "createPhi.H"

label pRefCell = 0;
scalar pRefValue = 0.0;
setRefCell(p, mesh.solutionDict().subDict("SIMPLE"), pRefCell, pRefValue);

The solver will select the pressure reference possition and reference value itself, so I just set the actual value in P file, is it right ?
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Old   December 2, 2009, 05:41
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Yes, specified value for p in 0 directory means difference from reference value. So if you set the reference value of p=0, values in 0/p means absolute value.
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