Why does y+ increase after computing?

aescarbi · December 13, 2009, 09:45

Hi, I would like to know why this happens:
for meshing near the wall, we compute the first node position for y+ = 1 with the java applet http://geolab.larc.nasa.gov/APPS/YPlus/. But, after solving, Fluent reports values of y+ of about 30 or higher at the same point. The flow is compressible (M = 1.1)
I appreciate any explanation.

thecfduser · December 14, 2009, 17:11

Hi
dear friend, the method that u are using to calculate y+ is bullshit...it does not work...there is no universal method to estimate y+ from Re.
The only way is, to do a simulation with Fluent, get y+, that refine ure mesh as much as u need...

teguhtf · December 16, 2009, 08:28

Hi,,
To get Y+ in FLUENT is By trial & error. I've tried that equation. and i dosnt work completely.
teguhtf

December 13, 2009, 09:45	Why does y+ increase after computing?	#1
aescarbi New Member Join Date: Dec 2009 Posts: 8 Rep Power: 17	Hi, I would like to know why this happens: for meshing near the wall, we compute the first node position for y+ = 1 with the java applet http://geolab.larc.nasa.gov/APPS/YPlus/. But, after solving, Fluent reports values of y+ of about 30 or higher at the same point. The flow is compressible (M = 1.1) I appreciate any explanation.

December 16, 2009, 08:28		#3
teguhtf Senior Member teguh hady Join Date: Aug 2009 Location: Saga, Japan Posts: 222 Rep Power: 18	Hi,, To get Y+ in FLUENT is By trial & error. I've tried that equation. and i dosnt work completely. teguhtf __________________ Now Or Never!!!

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December 14, 2009, 17:11		#2
thecfduser Senior Member karine Join Date: Nov 2009 Posts: 158 Rep Power: 17	Hi dear friend, the method that u are using to calculate y+ is bullshit...it does not work...there is no universal method to estimate y+ from Re. The only way is, to do a simulation with Fluent, get y+, that refine ure mesh as much as u need...