Abstract

An aerofoil commonly used in aerospace engineering to produce lift is adopting to the motorsport industry for downforce production and improving traction during cornering. This paper investigates aerofoil surface modification through ‘golf ball dimpling’, used to reduce flow separation behind a golf ball. The studies given by other researchers have shown that this type of design can have a positive effect on improving aerofoil performance. However, no optimization information of dimple sizing is given in literature. Therefore, three types of dimpling size of 5, 10 and 15 mm is applied to the surface of a NACA 6615 wing at 25% chord length from the leading edge in this study using Computational Fluid Dynamics (CFD) as an initial design process. A physical model made using 3D printing additive manufacturing (AM) method is tested at angles of attack (AoA) ranging from 0o to 20o with increasing wind speed up to 30 m/s in a subsonic wind tunnel. Experimental and CFD results show that the smallest dimple size provides the most significant increase on lift to drag ratio at high AoA above 10°. This ratio increases further with the wind speed, indicating a high AoA wing favours downforce to improve drag reduction performance.