Minimum grid size allowed for RANS?

luckyraymond · May 17, 2019, 03:52

Hi All,

To resolve some non-turbulence small-scale details in high-speed flows, I would like to use a finer resolution.

Using DNS or LES would make better sense, but my current code is RANS-based.

Is there a general rule or something?

LuckyTran · May 17, 2019, 14:30

There isn't a minimum size for RANS. You can go as small as you like until the fluid particle model is no longer valid (no more continuity or navier-stokes).

AshwaniAssam · May 23, 2019, 01:49

If you are using low Reynolds number RANS model, you have to ensure near the wall y+< 1 or 2.

May 17, 2019, 03:52	Minimum grid size allowed for RANS?	#1
luckyraymond New Member Join Date: May 2019 Posts: 4 Rep Power: 7	Hi All, To resolve some non-turbulence small-scale details in high-speed flows, I would like to use a finer resolution. Using DNS or LES would make better sense, but my current code is RANS-based. Is there a general rule or something?

May 17, 2019, 14:30		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,683 Rep Power: 66	There isn't a minimum size for RANS. You can go as small as you like until the fluid particle model is no longer valid (no more continuity or navier-stokes). BlnPhoenix likes this.

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May 23, 2019, 01:49		#3
AshwaniAssam Senior Member Ashwani Join Date: Sep 2013 Location: Hyderabad Posts: 154 Rep Power: 12	If you are using low Reynolds number RANS model, you have to ensure near the wall y+< 1 or 2.