CFD Online Discussion Forums - Questions about the Baldwin-Lomax model

I have read a lot books and paper about the Baldwin-Lomax model and I think I have a good understanding of how it works and its implementation.
I am trying to apply the in incompressible turbulent flow over an airfoil
and I have a few question:
when applying the model in the wake region , what is the definition of y in the function F(y) and F_KLEB(y) and from where it is measured(the reference line )???
some say it's the wake central line ( line of min velocity in the wake ) others say it's the hor line eminatinf from the airfoil TE.
Another one : F(y) can have multiple max. which max should
some say it's the max with min y

That's all , Thank you very much