Aerodynamics

Abstract

Vehicle aerodynamics has its roots in aviation, and the same is true for the related experimental techniques. The wind tunnel is the key carry-over element. Wind tunnels have been adapted stepwise to meet the specific needs of vehicle aerodynamic studies. Three areas of development must be mentioned: With vehicles a much greater blockage can be tolerated; to simulate the relative motion between vehicle and road or track different belt systems and mechanisms to reproduce wheel rotation have turned out to be useful; for tests in various climates a variety of specialized smaller wind tunnels have been developed. Measurement techniques are very much the same as in aeronautics at low Mach number and increasingly particle image velocimetry (PIV) is being applied to study the complex flow fields around vehicles. Nevertheless, flow visualization and photogrammetry still remains an indispensable tool for a quick evaluation of different geometries, also for dynamic flow conditions.