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September 24, 2015, 04:09 |
density change with pressure
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#1 |
Member
Lida
Join Date: Apr 2015
Posts: 39
Rep Power: 10 |
Hi everyone
I modeled a gas flow in a pipeline.because of the lack of availability of proper boundary condition in outlet I should use outflow boundary condition in outlet, so i have to use incompressible model and in fact the flow is incompressible.so I can't use ideal gas model and choose floating choice in operating condition.but because of the high pressure change in the pipeline I should verify density change with pressure.all of fluent models for changing density in material tab is are functions of temperature.so I wrote a udf for density changing with pressure and i interpreted it and there was no problem.but when I run the program, it stops in first iteration and shows the following error: Error: Floating point error: invalid number Error object: #f and this is my udf: #include "udf.h" DEFINE_PROPERTY(cell_density, cell, thread) { real ro; real press = C_P(cell, thread); ro=1.8495e-6*press; return ro; } the inlet pressure is 1723689 pa. I will be really thankful if anyone could help me with this problem |
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September 24, 2015, 06:51 |
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#2 |
Senior Member
Bruno Machado
Join Date: May 2014
Posts: 271
Rep Power: 12 |
just to be sure this is not the problem, can you try to compile it? sometimes, interpreted UDFs does not work properly.
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September 24, 2015, 14:01 |
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#3 |
Member
Lida
Join Date: Apr 2015
Posts: 39
Rep Power: 10 |
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September 26, 2015, 11:57 |
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#4 |
Member
Lida
Join Date: Apr 2015
Posts: 39
Rep Power: 10 |
is there any other idea or anyone else who could help me with this problem??
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