Computational Fluid Dynamics Analysis of Inverted, Multi-Element Airfoils in Ground Effect

Formula SAE cars are formula-styled race cars designed to race on an autocross circuit. The autocross circuit is mostly comprised of turning sections as well as a limited amount of straight sections for passing other cars. Highly competitive cars in the competition implement aerodynamic devices to generate negative lift for the race car. This negative lift, or downforce, increases the amount of traction between the race car’s tires and the ground ultimately allowing the drivers to turn at faster speeds. Commonly used aerodynamic devices are a front and rear wing; the wing cross sections are defined by configurations of multiple 2D airfoils extruded across the wing’s span. This thesis focuses on the research to systematically design the front wing sections of a Formula SAE race car by studying characteristics of high lift, inverted airfoils in ground effect in order to maximize the negative lift. Five high lift, single element airfoils are firststudied at multiple angles of attack from which three superior airfoils are chosen and used in a follow-up study that performs flow simulations of these airfoils at various heights above the ground. A second study aims at combining the single-element airfoils into a two-element airfoil configuration to further increase the negative lift by choosing a flap; the flow fields of two-element configurations are computed at various angles of attack and height above the ground, including the vertical and horizontal gap between the main element and the flap. Based on this study, a two-element configuration with a main element and flap is selected to obtain the maximum negative lift