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define hydrostatic oressure condition

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Old   May 16, 2016, 10:21
Default define hydrostatic oressure condition
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sina
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Hi foamers!
i'm modeling two phase case consist of water and brine. and i have a tank full of water and then a jet ob brine comes in to the tank thorough the nozzle. so i should have hydrostatic pressure condition in the tank, how can i define it?
and i should tell u that i'm using twoPhaseEulerFoam as solver. and as u know it needs a refPiont . i know there is something like this in FLUENT( operating condition) and there we can introduce a point even out of the boundary with 1e05 pa pressure. but in OP it is not possible to set the point out of the boundary. i introduced a pint in top corner of the domain and i set the pressure 0:
PIMPLE
{
nOuterCorrectors 3;
nCorrectors 1;
nNonOrthogonalCorrectors 0;
//
pRefCell 102;
pRefValue 0;
//
}

after running the model values of p and p_rgh have big values ! liek 6e04
(the height of the tank is 0.5m !)
but there is one point that is interesting between wrong values of P and P_rgh
and that is correct differences of pMean
for example with consideration 0.5 height we must have abour 5000 pa difference between bottom and top of the tank
and it is visible :
top value :6.08e04
bottom value:6.574e04
the values are wrong but the difference is about ~=5000 and correct
so what is going on ?
any help would be appreciate
Regards!
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Old   May 16, 2016, 13:02
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Mahdi Hosseinali
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Pressure boundary condition:
the value you define at 0/p is the hydrostatic pressure for your case (if you are not solving compressible), so just set the pressure there.
Since you are setting a fixedValue pressure there and not zeroGradient, then it's best if you put the pRefCell on the same boundary and set the pRefValue to the same value at your boundary condition. I'm not sure but I think since you have set your p value at some boundary it is neglecting the 0 pRefValue and is calculating base on your boundaries.
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Old   May 16, 2016, 15:27
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sina
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Hi Mahdi! thank u
I should say that my problem has compressibility! because I have tank with for walls and two symmetry plane, am I write ?( about compressibility ) and I just symmetry and wall boundary conditions
what do u mean about value of pressure in pressure condition?
internal field or boundary field ?
thank u very much
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