An Analysis of the Differences in Aerodynamic Drag among Bullet-shaped, Canted Nose at Subsonic Velocities

Abstract

Drag force is very important for high-speed rail’ s energy efficiency and operating speed. This study compares bullet-nosed and canted-nosed train designs through meta-analysis of existing experimental data and verifies the validity of the possible explanations through existing simulations. The result shows that the bullet-nose train can reduce 29.2% of drag force in 41.66 m/s and 35.6% in 79.1667 m/s, which primarily because of a better pressure management and the reduction of flow separation. Although it is superior in aerodynamics, the durability of the canted-nose design reflects necessary compromises on crosswise stability and space requirements. These findings provide a quantitative guidance for the superiority of bullet-nose in reducing drag force compares to canted-nose. Moreover, this paper analyzes the cause and the physical principle behind the phenomenon by dividing the composition of drag force. Also, this study reveals the balancing between aerodynamic performance with other critical design considerations in current and future train development.