how to check y+ validation for Aerodynamics
 

hi
as you know Y+ value dependent on friction velocity , i want to test a vehicle aerodynamics and Gaining it's drag coefficient, also i read some articles in this website about Y+ but i don't realize Y+ significance for aerodynamic test , because on the different points of vehicle surface friction velocity is different with other points so Y+ value may change too much !
as i said now i have 2 problem ; 1-for aerodynamics analysis i should keep Y+ value in specified rang and if it is true what is this rang ?
2-when friction velocity is different is vehicle surface how i can keep Y+ value to gain a accurate drag coefficient ?