how to calculate y+
How do you calculate y+ and in which range should it be?

Re: how to calculate y+
hi,
Y+ = Y/Nu * Utau Y = distance from the nearest wall, Nu = Kinematic viscosity, Utau = skin friction velocity. In the region nearest to the wall known as the viscous sublayer (Y+ <30) Utau is given by Newtons law  Utau = sqrt((Mu*(du/dy))/rho) Where Mu is dynamic viscosity = Nu*rho rho  density Outside the viscous sublayer the loglaw is asssumed to aspply. This states U+ = (1/K) log(y+) + C or U+ = (1/K) Log(Ey+) With K= von Karman constant = 0.41 C = 5.5 or E = 9 Good luck Tim 
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