Estimating Y+

The screenshot you are showing represents a user defined relationship for estimating the y+ in AcuConsole.  If you click on the 'Whats this' icon in the main toolbar, then click on the 'Power' entry in the panel, it will show the equation that is used to determine the Y+ for this use case: 

Y+ = (Y1/coeff *Len) * Re^power

Y1 = first layer height

coeff = Coefficient

Len = Length Scale

power = Power

The Reynolds Number is estimated based on the material properties supplied by 'Material model' and the length and velocity scales.

Note that the 'Estimated Y+ method'=User is typically only used if you are working with an application for which the 'Flat Plate' and 'Pipe' relations don't work well, and you know the proper scaling.  In my experience, the predefined approaches are pretty good for most applications.  I use 'Pipe' for internal flows and 'Flat Plate' for external flows.

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Thanks guru for the reply /emoticons/default_smile.png' alt=':)' srcset='/emoticons/smile@2x.png 2x' width='20' height='20'> I'm doing external aerodynamics, So I think I can stick with the flat plate as you said. But  I'm still curious to know what  the power & coefficient are related to materials - like air ?? I mean its the power & coefficient of what ???

No problem!  The power and coefficient would be related to the geometry of the simulation.  Basically, it's there for users that have complex applications for which they have developed their own relationships between Re and Y+.  So, it really just serves as a general expression that you can tune to your specific application.