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-   -   Incompressible converges, ideal gas goes nuts (http://www.cfd-online.com/Forums/fluent/71750-incompressible-converges-ideal-gas-goes-nuts.html)

psigcochair January 13, 2010 16:48

Incompressible converges, ideal gas goes nuts
 
I'm flowing gas through some tiny inlets into a big nozzle. Incompressible converges, but when I switch to ideal gas, FLUENT has a coronary.

The velocities aren't very high, ~105 ft/s. I'm new to this, and any suggestions are greatly appreciated!

Thanks,
Michelle :confused:

herntan January 13, 2010 23:48

make fine meshes on inlet.

psigcochair January 14, 2010 08:48

The inlet mesh is very fine. The inlets are 0.032" diameter, and they have +100 faces/tets on them.

I believe the problem is when I switched to ideal, I received a warning (in the Check Case) that I had 0 gauge pressure at the boundarys. While the operating pressure was 95 psi. So I switched them, which was the WRONG thing to do!

Because my mach is <0.1 I should have left it the same. So I'd really like it if FLUENT wouldn't give me warnings that don't really apply to me. This is not the first time this has happened.

herntan January 14, 2010 21:14

you mean u change the operating pressure to 0psi and change the gauge pressure to 95psi ??

Fluent give this warning all the times. I don't think its a bad thing. People who understand what is operating pressure and what is gauge pressure should be understand what it trying to warn.

So does ur simulation works now?


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