Numerical Study of the Boundary Layer Separation Control on the NACA 0012 Airfoil using Triangular Rib

Abstract

This study includes a numerical simulation to investigate the aerodynamic behavior of the air flow around the surface of the NACA0012 airfoil, with and without a triangular rib. The triangular rib was used on the upper surface of the airfoil with size of 2% of the total chord length and variously located at 50, 70 and 90 percent of the chord length from the leading edge, separately as a passive control technique. Workbench-Fluent 17.2 version software was used to simulate the flow at 7 m/s freestream velocity (Re = 78,000), various attack angles (0° to 22°) and chord length of 168 mm. The results indicated the presence of the triangular rib on the airfoil's upper surface, at low angles of attack (less than 12°), was a negative for the lift and drag results, at the angle of 12° it was a positive only for the location of 90%, while at the higher angles it was a positive for all locations and for all results where the lift increased and drag decreased. Therefore, the NACA0012 airfoil's performance (lift to drag ratio) was significantly enhanced but, at 22°, it had a very small effect for all results. It was concluded that the rib's presence at 50% location delayed the stall angle by two degrees (from 14° to 16°).