Numerical Study of Performance of Airfoil with Sinusoidal-Shaped Leading Edge at Low Wind Speed

Abstract

Increasing the airfoil’s angle of attack is one way to enhance its performance. The biggest issue, though, is that an airfoil will eventually stall when its angle of attack increases beyond its operating angle. The performance of an airfoil could be improved by a technology that allows increasing its operating angle. This study uses airfoils with NACA 4412 cross-section profiles to numerically simulate how sinusoidal bumps, sometimes known as tubercles, at an airfoil's leading edge affect performance. Two computational software, GAMBIT and Fluent, were employed. The simulation was conducted using the shear stress transport (k-ω) turbulence model. The parameters examined at low Reynolds number based on 6 m/s air velocity are lift, drag, angle of attack, bump height, and flow separation (or stall). The results show that the convectional airfoil model achieved a higher maximum lift coefficient than the bumpy airfoil between 5-degree and 15-degree angles of attack but quickly dropped below that of the bumpy airfoils due to stall effects. The max lift coefficient for the convectional airfoil is 1 at around 12-degree angle of attack before dropping, and that of bumpy one stayed at a max of 0.91 from 12-degree up to 15-degree. The drag coefficient of the conventional airfoil increases with angle of attack up to 15-degree, and continue to increase along a straight line up to the last angle (25-degree). The bumpy airfoil model drag coefficients variation with angle of attack shows similar trend with that of conventional one, only that between 5 and 20-degree angle of attack, the bumpy airfoil has greater drag coefficients. The lowest and highest drag coefficients for both models are approximately 0.03 and 0.44.