Prism cell near wall layer ASPECT RATIO
 

Hello everyone!
I'm working on an HVAC duct simulation (internal, steady & turbulent flow of air at constant density). I'm interested in studying what effect does the aspect ratio of the near wall prism layer have on the boundary layer resolution (I have the first cell height and related parameters handled).

What should be the aspect ratio of the near wall prism cells in this scenario?
Any help/suggestions are highly welcome!!

:confused: