Supersonic/Inlet Gauge Pressure

xavier_e · April 23, 2010, 06:20

Hi
I am Xavier and i am new to fluent.I am currently using fluent for the analysis of nozzle.Where i am confused what to enter the value for supersonic/inlet gauge Pressure in boundary condition.I am currently using this tutorial http://courses.cit.cornell.edu/fluent/nozzle/index.htm for fluent analysis of nozzle.

leonardo.morita · April 27, 2010, 09:17

This is only a first guess for the static pressure and normally it should not affect your results, so you can use an arbitrary value. However a good guess can help with convergence issues...

xavier_e · April 28, 2010, 04:47

Many people have said they same thing you did it is right for small pressure range(I think) .But when you go little higher say 12 bar then what ever value i am putting in supersonic/inlet gauge pressure either it gives floating point error or divergence detected.So i am guessing it is due to wrong value in supersonic/inlet gauge pressure.
Can you help me why this error?

[IMG=http://img33.imageshack.us/img33/6455/capturepox.th.jpg][/IMG]

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leonardo.morita · April 28, 2010, 05:01

hmm...honestly I've never done this kind of simulation, but I can suggest you to try a good initialization for your whole domain...and also to recheck all your boundary conditions
good luck

April 23, 2010, 06:20	Supersonic/Inlet Gauge Pressure	#1
xavier_e New Member Xavier Ekka Join Date: Apr 2010 Posts: 2 Rep Power: 0	Hi I am Xavier and i am new to fluent.I am currently using fluent for the analysis of nozzle.Where i am confused what to enter the value for supersonic/inlet gauge Pressure in boundary condition.I am currently using this tutorial http://courses.cit.cornell.edu/fluent/nozzle/index.htm for fluent analysis of nozzle.

April 28, 2010, 04:47	supersonic/inlet gauge pressure	#3
xavier_e New Member Xavier Ekka Join Date: Apr 2010 Posts: 2 Rep Power: 0	Many people have said they same thing you did it is right for small pressure range(I think) .But when you go little higher say 12 bar then what ever value i am putting in supersonic/inlet gauge pressure either it gives floating point error or divergence detected.So i am guessing it is due to wrong value in supersonic/inlet gauge pressure. Can you help me why this error? [IMG=http://img33.imageshack.us/img33/6455/capturepox.th.jpg][/IMG] Uploaded with ImageShack.us

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April 27, 2010, 09:17		#2
leonardo.morita Member Leonardo Giampani Morita Join Date: Apr 2009 Location: Paris, France Posts: 58 Rep Power: 17	This is only a first guess for the static pressure and normally it should not affect your results, so you can use an arbitrary value. However a good guess can help with convergence issues...

April 28, 2010, 05:01		#4
leonardo.morita Member Leonardo Giampani Morita Join Date: Apr 2009 Location: Paris, France Posts: 58 Rep Power: 17	hmm...honestly I've never done this kind of simulation, but I can suggest you to try a good initialization for your whole domain...and also to recheck all your boundary conditions good luck