y plus contours

Necmettin · June 6, 2009, 12:21

Hi everyone,

I have a question regarding the y plus value in Fluent. By its definition y+ = (y*friction velocity)/kinematic viscosity. Since friction velocity and kinematic viscosity do not change, we expect to see the y plus value to increase as we depart from the wall. On the other hand for my external flow analysis when I display/contours/y plus, I see that y plus value decreases from wall y plus value to zero instead of increasing.

Do any of you have any idea? May it be due to a different formulation of y plus in Fluent or am I making a mistake?

Thanks in advance,
Necmettin

vishyaroon · June 6, 2009, 16:33

In most commercial softwares y+ is a parameter computed on the wall. So the value is determined by the first wall distance. This is why for the grid points away from the wall this will be 0.

June 6, 2009, 12:21	y plus contours	#1
Necmettin New Member Necmettin Cevheri Join Date: Jun 2009 Posts: 1 Rep Power: 0	Hi everyone, I have a question regarding the y plus value in Fluent. By its definition y+ = (y*friction velocity)/kinematic viscosity. Since friction velocity and kinematic viscosity do not change, we expect to see the y plus value to increase as we depart from the wall. On the other hand for my external flow analysis when I display/contours/y plus, I see that y plus value decreases from wall y plus value to zero instead of increasing. Do any of you have any idea? May it be due to a different formulation of y plus in Fluent or am I making a mistake? Thanks in advance, Necmettin

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June 6, 2009, 16:33		#2
vishyaroon Senior Member Aroon Join Date: Apr 2009 Location: Racine WI Posts: 148 Rep Power: 17	In most commercial softwares y+ is a parameter computed on the wall. So the value is determined by the first wall distance. This is why for the grid points away from the wall this will be 0.