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ehsan March 9, 2009 07:08

Hi, I am trying to solve a

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:

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

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


type symmetryPlane;

type zeroGradient;


type slip;

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


hamcer March 10, 2009 05:45

Hi ehsan, I use also a Open
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?.


ehsan March 10, 2009 14:15

Dear Hamdi, It is micro-noz
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?


ehsan March 11, 2009 12:52

Hi Hamdi, I use OF 1.5, may
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.


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