Research on Aerodynamic Drag Reduction by Vortex Generators by Masaru Koike, Tsunehisa Nagayoshi, Naoki Hamamoto
Abstract - One of the main causes of aerodynamic drag for sedan vehicles is the separation of flow near the vehicle’s rear end. To delay flow separation, bump-shaped vortex generators are tested for application to the roof end of a sedan. Commonly used on aircraft to prevent flow separation, vortex generators themselves create drag, but they also reduce drag by preventing flow separation at downstream. The overall effect of vortex generators can be calculated by totaling the positive and negative effects. Since this effect depends on the shape and size of vortex generators, those on the vehicle roof are optimized. This paper presents the optimization result, the effect of vortex generators in the flow field and the mechanism by which these effects take place.