Numerical study on the influence of the nose and tail shape on the aerodynamic characteristics of a Hyperloop pod

The Hyperloop has been proposed as a high-speed vactrain system for freight and passenger transport. Given that the Hyperloop aims to operate at subsonic to supersonic speeds, the aerodynamic environment within the tube needs to be carefully considered. The shape of a pod is also very important with regard to reduction of aerodynamic drag and lift. Therefore, this study investigates the influence of the nose and tail shape of a Hyperloop pod on its aerodynamic drag, lift, and pitching moment by comparing five pod shapes: symmetrical, downward nose–upward tail (NdTu), upward nose–upward tail (NuTu), downward nose–downward tail (NdTd), and upward nose–downward tail (NuTd). Six pod speeds from 100 to 350 m/s at 50-m/s intervals are simulated under steady-state conditions and the shear-stress transport k-ω model. The shape of the nose and tail has only a slight effect on aerodynamic drag, with minor differences in drag acting on NdTu, NuTu, NdTd, and NuTd. The symmetrical design producing a drag that is 10.7% lower than that of the other designs at a pod speed of 350 m/s. In contrast, aerodynamic lift strongly varies with a change in the shape of the nose and tail, especially for pod speeds of 250 to 350 m/s. A downward tail produces positive lift, while an upward tail experiences negative lift. The lift acting on the tail of the pod accounted for more than 90% of the total lift. Additionally, the upward noses of the pod also produce negative lift. Based on these results, pod designs with an upward nose and tail should be avoided. The results of this study thus provide useful guidelines for the design of pods for the Hyperloop.