Investigation of aerodynamic shape optimization of cross-sectional body of high-speed train

Abstract

A train body’s cross-sectional shape has a significant impact on aerodynamic drag and operational safety in high-speed trains (HSTs). This study extracts five design variables from a real-world HST body: height, width, side arc radius, arc radius at the connection between the side and the roof, and arc radius at the connection between the side and the train’s bottom. The cross-validated Kriging surrogate model and the genetic algorithm are used to perform two types of aerodynamic optimization, with the cross-sectional area as a constraint. Cross-sectional shapes are optimized in both windless and windy conditions. Numerical results indicate that in a windless environment, the aerodynamic drag coefficient of the whole train is reduced by 2.4%; in a windy condition, the aerodynamic drag coefficient of the entire vehicle is reduced by 2.4%, and the aerodynamic lateral force of the leading car is reduced by 37.8%. These suggest that a flat and wide shape helps to reduce not only overall aerodynamic drag in a windless environment but also aerodynamic load in a windy environment, which can be accomplished by reducing the area of the side wall and top region, lowering the train body’s height, increasing its width, and lowering the radius of the side and top arcs.

Keywords

cross-section / multi-objective optimization / Kriging model / aerodynamic design / high-speed trains

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