Numerical Study on Tube Shape Influence on Aerodynamic Drag in an Evacuated Tube Transport System

Abstract This study investigates the impact of tube shape on the aerodynamic forces experienced by an evacuated tube transportation (ETT) system. Using CFD simulations, the study explores various tube geometries to discern their influence on aerodynamic forces, particularly drag, critical for high-speed travel. The investigation centers on a standard tube shape derived from maglev design, considering parameters like tube radius, guideway height, and eccentricity between the tube and pod, with pod speeds ranging from 50 to 350 m/s. The study also examines the influence of the levitation air gap. The findings reveal that aerodynamic drag is mainly dictated by the blockage ratio (BR), especially within the range of 0.5 < BR < 0.68. An empirical formula is proposed to estimate aerodynamic drag based on BR and pod speed, validated against CFD results with a maximum error of 6.26%. These insights guide the aerodynamic design of vacuum-based ETT systems.