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Old   April 12, 2015, 09:03
Default FLUENT Q-Criterion
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I am currently running some LES on an Ahmed Body and pulling out iso-contours of Q-criterion for vortex analysis. However, I would eventually like to move on and stop using LES in favor of a turbulence model. The problem is that when I switch from LES, Fluent no longer calculates Q-criterion for me, as in I cannot select it when I go to export or output my data. Unfortunately, Q-criterion is much more complicated than say Vorticity and cannot simply be calculated as such. Does anyone know how to get Fluent to give me Q-criterion?
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Old   April 12, 2015, 19:15
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If you can't find a Fluent UDF of Q Criterion that someone has already created and posted online then you may need to create your own. Have a read of this post on Lambda-2 (similar to the Q Criterion) because they provide equations and code.
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Old   April 13, 2015, 04:49
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You can find a custom field function for Q here:
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Old   April 14, 2015, 11:15
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This is exactly what I wanted, thank you so much!
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