Aerodynamic Analysis of Flow over NACA 0015 Aerofoil with Vortex Generators and Leading Edge Tubercles

Abstract

Basic airfoils are engineered to excel in the pre-stall regime, yet only a limited number are optimized for performance in the post-stall regime. Enhancing an airfoil performance in the post-stall regime requires modifications, with flow control devices. Several active and passive flow control devices including winglet, fence, slit, slot, Boundary Layer suction, blowing etc. have been widely reported in the literature, which have been proved successful in enhancing the performance of airfoils. In the present work an attempt is made to study the use of vane-type wedge Triangular vortex generators and tubercles which are emerging as superior passive flow control devices. Computational Fluid Dynamics (CFD) has been utilized to analyze the flow over a NACA 0015 airfoil at a free stream velocity of 10m/s and a Reynolds number (Re) of 70,000. Performance of three different combinations of the vortex generators combined with leading edge tubercles have been analyzed in CFD software. The acquired results have been validated experimentally with the tests performed in a low-speed subsonic wind tunnel. Based on the experimental findings, the wing model experienced stall conditions at an angle of attack of 18°, with the decrease in lift exhibiting a notably gradual decline rather than a sharp drop-off. This phenomenon can be attributed to the stream wise vortices generated by the tubercles and vortex generators, which aid in prolonging flow attachment to the surface. Consequently, this delay in flow separation mitigates the creation of pressure drag at the wing trailing edge.