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Old   March 9, 2009, 07:08
Default Hi, I am trying to solve a
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ehsan
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Hi,

I am trying to solve a small-scale C-D nozzle via rhocenteralfoam, w.o. applying any back pressure, so I expect full supersonic flow. My solution does not show correct behaviour as I see in divergent section of nozzle, there is a small decrease in velocity followed by increase. In temperature profile I also see a small increase (followed by expected decrease).
I think maybe I apply B.C incorrectly. My pressure B.C is:
Pressure B.C:

boundaryField
{
inlet
{
type totalPressure;
p0 uniform 1.0487e5;
U U;
phi phi;
rho none;
psi none;
gamma 1.4;
value uniform 1.01e5;
}

outlet
{
type waveTransmissive;
field p;
phi phi;
rho rho;
psi psi;
gamma 1.4;
fieldInf 1.01E5;
lInf 1.0e0;
value uniform 1.01E5;
}

top

{
type symmetryPlane;
}

bottom
{
type zeroGradient;
}

wall

{
type slip;
}
}

I put the value of atmospheric pressure for fieldInf and value, as shown above. The length of nozzle is about 200 micron.

Regards,
Ehsan
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Old   March 10, 2009, 05:45
Default Hi ehsan, I use also a Open
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hamdi
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Hi ehsan,

I use also a OpenFoam to solve Nozzle problem about an hydraulic turbin (pelton) , for that, I use a RasInterFoam solver. but I didn't found a rhocenteralfoam in OF , is it a solver?!
Other thing, why you use a type slip for wall condition?.

Hamdi.
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Old   March 10, 2009, 14:15
Default Dear Hamdi, It is micro-noz
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ehsan
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Dear Hamdi,

It is micro-nozzle, so I need to use slip B.C to capture rarefaction effects. The solver is: rhoCentralFoam

Do you put an extended region outside your nozzle to apply pressure B.C or you had solved only the main nozzle?

Thanks
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Old   March 11, 2009, 12:52
Default Hi Hamdi, I use OF 1.5, may
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ehsan
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Hi Hamdi,

I use OF 1.5, maybe this solver is not in the old version.
Is it possible that you email me the boundary (p-u-t) of your geom so that I can be able to see the it in paraview? I see it is 3-d axisymmetric.

Email:ehsan.roohi@gmail.com

Thanks
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