Mode and regime identification for a static NACA0012 airfoil at transitional Reynolds numbers

This work examines the flow structure modes in the boundary layer and in the wake of a NACA0012 airfoil in static conditions at transitional chord-based Reynolds numbers (Rec ), for small angles of attack (α ). A laminar mode, with a laminar separation of the boundary layer and laminar Karman streets in the wake, was first observed for Rec = 0°. For 77 000 and α , a critical transition mode consisted of a long bubble followed by a turbulent separation, and a less structured vortex street in the wake of the airfoil.