Reasonable figure of subsonic train front and rear in evacuated tube transportation based on aerodynamics consideration

Abstract

Based on hypothesis of incompressible viscous flow, 2D stable flow field and moving tube wall conditions, as well as Navier-Stokes equation and κ-ε two-equation turbulent models, the aerodynamic drag imposed on the trains with different front/rear shapes which run at subsonic speed in evacuated tubes were calculated respectively. By analyzing the calculating results, it could be found that the streamlined train front/rear are effective for reducing aerodynamic drag acted on ETT trains running at subsonic speed and in partial vacuum tube from 101.25∼10132.5Pa, and it is apparently more effective for reducing aerodynamic drag acted on trains in the tube to attach both taper front and rear than only taper front. The optimized taper length of the ETT train front/rear is 1.5∼2 times of the train body section diameter. In addition, pointed out that a vertically symmetric taper is right for the ETT train front/rear. © the authors.