[PvS]

Hello,


I have read almost every thread about Yplus and K-W SST model. I have set my wall function to Automatic with enabled Transitional Turbulence to Fully Turbulent.

Now could I just ask one simple question

Does my Yplus has to be less than 1 (y+<1) when the automatic wall function is on! and how many Inflations layers must I use near the wall for my mesh?

Im dealing with a Reynolds Number of approximatley 5000
my hydraulic diameter is about 0.003m


If I have to give 25-30 inflation layers to make the simulation more accurate what is the recommended growth rate and the inflation layer option

1) first layer thickness?
2) LAst Aspect ratio?
3)Total Thickness?


I know The SST model is based on the k-omega model and has the same automatic wall treatment
–Improves on standard k-omega model, which proves too sensitive to freestreamturbulence.
–Accounts for transport of turbulent shear stress and gives highly accurate predictions of the onset and the amount of flow separation
–This is a good default choice

Could somebody please clear this for me because I've been hearing that if you re using automatic wall function you do not need to be worrying about Yplus But however when check my Yplus in CFX post or when I monitor my Wall plus on my geomerty I get y+=22 and when I dont put any inflation layers the solution oscillates and does not reach the residual criteria.

So please help!