Aerodynamic Investigation and Design of Dimpled-Surface Airfoil for UAV Propellers

Abstract

This project focuses on studying the aerodynamic performance on dimpled airfoil for drones or UAVs propeller applications. The aim is to check if dimples will improve the efficiency of the structure by increasing lift to drag ratio and stall angle or decreasing drag force on the airfoil. The surface modification was done by considering the different arrangement and location of dimples at various Reynold numbers. Dimples help in reducing pressure drag when the airfoil is at larger angles of attack, as the angle of attack is increased, the wake formation starts to occur due to boundary layer separation. Dimple effects on the airfoil surface in same manner of what vortex generator does. Both methods aim to produce turbulent boundary layer in which wake area is reduced therefore reducing pressure drag. For the design process, ANSYS FLUENT was used to computationally investigate the effects of using dimples over the airfoil surface of NACA 2412. A comparative study was conducted between a normal airfoil (no dimples) and dimpled-surface airfoil, at different angles of attacks. It has been found that lift to drag ratio was increased by an improvement of 39.9%. It has been found that the flow separation on the NACA 2412 was delayed by the dimples effect. The critical angle of attack, which the stall occurs was also increased.