[MHP]

Hello,
I am tiring to model a 2D semicircle on a rigid surface(as a bump on the ground)using FLUENT for variety of Re numbers,but I couldn't find out where the separation point is? Using XY plot there are only regions that shows the skin friction coeff. came around zero, so which of them are separation point? Is it good to use skin friction coefficient plot? How far should the grid be? I use 20D for upstream and downstream, is this assumption satisfy the modeling?
At last is there any articles that do this modeling experimentally so I can check the separation point with changing the Re number?
Thank you very much friends.