Thankys for this many answers 
and to check my results @ROHIT_SR,
yes i double the result to get the cell height.
@DaleKramer,
thank you for your explanation, i will try your programm tomorrow. I hope i works with my simulation type.
The most used source is this good post from @jousefm Post, but i use the a different fomrular for the skin friction coefficent, its the equastion from Schlichting in that source Link.
I will get back to you tomorrow
Best regards
Kai