Formula for velocity in buffer layer of turbulent boundary layer -- CFD Online Discussion Forums

February 3, 2012, 12:57	Formula for velocity in buffer layer of turbulent boundary layer	#1
nickvinn New Member Nikolay Vinnichenko Join Date: Nov 2010 Posts: 14 Rep Power: 16	Hello! I was calculating turbulent viscosity according to Baldwin-Lomax model for the fixed velocity field of flat plate turbulent boundary layer and had problems with too low viscosity in the outer layer of the model. Now I realize that the velocity profile by Reihardt $u^+=ln(1+\kappa y^+)/\kappa+7.8(1-exp(-y^+/11)-y^+exp(-y^+/3)/11)$ , which I was using, yields bad F-function with peak located too close to the wall. I changed for piecewise $u^+=piecewise(y^+<5, y^+, y^+<30, 5*ln(y^+)-3.05, ln(y^+)/\kappa+5.5)$ . It yields F-function with correct global maximum. However, is discontinuous, so another local maximum exists closer to the wall. I'm afraid that for some values of parameters I can take it for the right one. Is there any analytical expression for velocity profile with correct description of buffer layer () and continuous derivative?

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