Optimization of crosswind stability for high-speed trains: Aerodynamic analysis of leeward winglet deflection angles

Abstract

The stability of high-speed trains under crosswind conditions has become a key consideration in aerodynamic design. As running speeds continue to increase and car body weight decreases, crosswinds pose a greater risk to train safety, significantly lowering the critical wind velocity. Therefore, developing strategies to enhance crosswind stability is essential. This study focuses on the leeward region adjacent to the train body, where separated flows with large vortices generate significant negative surface pressure. Enhancing this negative pressure distribution is proposed as a potential method to improve a train’s resistance to overturning. To achieve this, winglets are installed on the leeward side as a flow control measure, and their effects at different deflection angles are evaluated. The influence of five deflection angles on the leeward-side flow field and aerodynamic loads is analyzed, considering the head, middle, and tail cars. Results indicate that a deflection angle of 90° optimally reduces the overall overturning moment by 27.6% compared to the baseline model in a three-car configuration. These findings highlight that optimizing the winglet deflection angle to approximately 90° can significantly enhance a train’s resistance to overturning, offering valuable insights for aerodynamic optimization in strong wind conditions.

Keywords

high-speed train / winglet / crosswind / passive flow control / leeward vortex

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Central South University