The process of wall function method

Baicang

Hello, I am solving a turbulent flow problem with wall function method. But I don't know the calculate process of wall function method. In my opinion,we guess a friction velocity u* first,from the following eq.(y+)=(yp)u*/v , we obtain y+,then from up/u*=1/x*ln(Ey+),where,up is the velocity at the first computational layer.up is not accurate, how about the next process? I don't know if my comprehension is correct, any help is appreciated.Thanks in advance!

Baicang