Using Race Car Aerodynamics To Teach Mechanical Engineering Students About Fluid Mechanics

Abstract

The study of racecar aerodynamics provides an interesting application for illustrating principles of fluid mechanics. Racecars are aerodynamically designed to minimize drag force and maximize downforce (unlike airplanes which are designed to minimize drag and maximize lift). Drag forces limit maximum speed and affect fuel consumption while downforce is used to provide stability when driving around corners. Racecars use various "appendages" and body contouring to provide downforce and decrease drag force. This paper describes a 2-3 week wind tunnel lab exercise designed to study the aerodynamics of racecars. The lab is used in a junior level introductory fluid mechanics course to teach mechanical engineering students about the principles of lift and drag and the relationship between pressure and velocity as described by Bernoulli's equation. We use several types of model racecars and students measure the lift (downforce) and drag as a function of velocity. In addition the students measure the pressure distribution on the surface of the model racecars and use Particle Image Velocimetry (PIV) to quantitatively measure the flow field around the car that contributes to the lift, drag and pressure measurements. By comparing the data from different car types students learn about lift and drag. This paper describes the experiments, explains how to instrument the cars, and presents a set of typical results for five different model car types.