Study on Ultra-Low Aerodynamic Drag Vehicle through Optimization of Rear Shape and Aerodynamic Drag Reduction Devices

Abstract

In this study, design of ultra-low aerodynamic drag vehicle was performed through optimization of rear shape and aerodynamic drag reduction devices. Sedan type vehicle was selected as a base model, which is being manufactured in these days. To reduce the aerodynamic drag, its rear shape was redesigned to square back type which is widely known as having low aerodynamic drag. Square back shape was designed by considering only the aerodynamic perspective. As a result, the aerodynamic drag was reduced. In order to minimize the aerodynamic drag of redesigned square back vehicle, optimization was performed. Roof angle, side angle and diffuser angle, which are the component of square back shape, were selected as the design variables. As a result of optimization, aerodynamic drag was decreased by 10.85% compared to initial square back shape. The relation between design variables and aerodynamic drag, together with the aerodynamic characteristics were obtained. Aerodynamic drag of optimal design was reduced by 29.25% compared to sedan type vehicle. To additionally reduce the aerodynamic drag, aerodynamic drag reduction devices(side air dam, under deflector, wheel arch cover) were installed to optimal design of square back type vehicle. As a result of installing aerodynamic drag reduction devices, aerodynamic drag was improved by 33.15% compared to sedan type vehicle.