correct turbulence model
I have a few questions about the correct selection of a turbulence model.
the flow is in the headspace of a tank exposed to ambient conditions. the headspace as a pressure outlet at the top. working fluid is air and since characteristic length is about 2 m, even for temperature difference of 5 K, rayleigh number goes in the transition region around 10e8 to 10e9
Is K omega model the only option for me?
Can I use K epsilon for this case?
Will K epsilon with RNG be a better choice?
If I want to use std wall functions for K epsilon, I have to keep the cell thickness at the wall pretty high, that makes the whole grid too coarse -- so I am clueless there.
If I go for K epsilon with enhanced wall, i know i need to maintain y+ around 1, but i have seen it go as high as 3. In one case, it went up to 10 -- IS that bad? will that give wrong results? Do I need to step back and rerun that time part with refined mesh? \
Please shed light on whatever questions you can.
thank you, CO2
Re: correct turbulence model
Hi, About the enhanced wall treatment, you may need to follow the instruction given by Fluent, i.e. maintain y+ around 1. you may need to refine.
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