How to add turbulence purtubation in the middle of the computational domain?
 

Hi, I am doing simulation of turbulence flow around an airfoil using LES in Fluent. the Reynolds number is 6e4 and there should be separation at the upper surface of the airfoil. But in my simulation I don't see any separation, and someone suggested that maybe I should add some pertubation near the leading edge of the airfoil to trigger the separation. I know how to add pertubation at the boundary, but I don't know how to do it near the leading edge (inside of the computational domain).

any suggestion is appreciated. Thanks in advance!

come on, can anybody help me out?