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Inlet pressure

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Old   May 30, 2010, 12:38
Red face Inlet pressure
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ali
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I simulated over expanded nozzle at 1 bar ambient , steady state with mass flow rate inlet condition. super sonic gauge presure i used 70 bar
now i wanted to change inlet pressure with respect to time .
i give in put using
#include "udf.h"
DEFINE_PROFILE(unsteady_pressure, thread, position)
{
float t, pressure;
face_t f;

begin_f_loop(f, thread)
{
t = RP_Get_Real("flow-time");
pressure = 200000+300*t;
F_PROFILE(f, thread, position) = pressure;
}
end_f_loop(f, thread)
}

and solved for 10 milli second
and saved file..
when i look at result no change in pressure , remains 70 bar
I did change the pressure inlet from constant to ydf pressure
someone can help
Regards
Ali
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Old   May 31, 2010, 19:15
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omid
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maybe it could be helpful

#include "udf.h"

DEFINE_PROFILE(unsteady_pressure, thread, position)
{
face_t f;

begin_f_loop(f, thread)
{
real t = RP_Get_Real("flow-time");
F_PROFILE(f, thread, position) =200000+300*t;
}
end_f_loop(f, thread)
}

Last edited by om1234; May 31, 2010 at 19:39.
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Old   June 2, 2010, 05:34
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Max
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If I understand you right, you are using a mass-flow inlet BC. In this case supersonic/initial gauge pressure is only used for initializing the solution and your udf will not have any effect for the rest of the computation.

cherrs
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Old   June 2, 2010, 08:01
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ali
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means i should give mass flow inlet using udf?
can you help how?
also if i have particles in flow how to give it using udf also?
plz help
Regards
ali
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