modelling udf-sourceterm for transitional flow

matthias

hi, i simulate a 2d transitional flow over an airfoil. since the flow is laminar at the beginning and turbulent at the end, i have to divide the area into a laminar and a turbulent zone. until now i did it by dividing the mesh into two zones. but this very costly because i have to design a new grid for every angle of atttack (the point of transition moves). there should be a possibility to simulate the transition with a udf source term. but i dont know how to do that. is there anybody, who has done that before and could help me(e.g. by sending me a example source-file)? thanks in advance