Key Takeaways & Executive Findings
- •• Leeward airbags significantly reduce lateral force and overturning moment coefficients, enhancing crosswind safety. • The top-mounted airbag (Model III) yields the best performance: lateral force coefficient reduced by 16.71% and overturning moment coefficient by 23.65%. • Airbags alter surface pressure distribution on the leeward side, improving aerodynamic stability. • Findings offer a novel passive aerodynamic solution for next-generation high-speed trains.
Abstract
The aerodynamic performance of a high-speed train deteriorates sharply under crosswind, severely affecting its operational safety. This paper adopted a three-car high-speed train as the benchmark and established leeward side (LWS) airbag-train models. Based on the three-dimensional steady SST k-ω two-equation turbulence model, this study investigated the aerodynamic characteristics of trains under crosswind at three different airbag’s installation positions. The results show that the airbags installed on the LWS change the surface pressure distribution on the LWS of the train body, lowering the lateral force coefficient and overturning moment coefficient, and the aerodynamic performance of the train under crosswinds is enhanced. The airbag structure located at the top of the LWS (Model III) shows the most significant improvement in crosswind performance that the lateral force coefficient is reduced by 16.71%, and the lift coefficient is increased by 17.95%, which collectively led to a decrease in the train’s overturning moment coefficient by 23.65%. The research findings provide a reference for improving the anti-overturning performance of the next generation high-speed trains under crosswind.
1. Introduction
With the continuous increase in running speed of high-speed trains and the reduction in train body’s weight, the interaction between the aerodynamic performance of train and surrounding environment has become increasingly significant [1−5], and the operational safety of trains in crosswind conditions has emerged as a critical issue. The strong crosswind significantly alters the aerodynamic features of the train, causing a large increase in the lateral force and overturning moment, which can result in the severe change to the train’s operational posture. In extreme cases, this can lead to derailments or overturning accidents, severely impacting the safety of train operation [6−12]. To address this issue, scholars have undertaken extensive investigations, including full-scale measurements [13, 14], numerical simulations [15−17], and wind tunnel tests [18−20].
To improve the aerodynamic performance of high-speed trains in crosswind, several measures have been implemented: the establishment of a strong wind warning system to guide train operating speed, optimization of the train’s aerodynamic shape, and installation of windbreak facilities [21−28]. For example, LIU et al [29] proposed the multiple attention layer based multi-instance learning (MAL-MIL) model, which estimates the likelihood of the actual wind speed exceeding a threshold based on predicted wind speeds, thereby determining the safe operating speed of the train. ZHANG et al [30] studied the impact of fully enclosed pantograph fairings on the train’s crosswind performance. The results showed that the optimal wind resistance was achieved when all pantographs were enclosed with fairings, leading to smoother airflow around the pantograph area. DONG et al [31] investigated the relationship between train cross-sectional geometric parameters and overturning moments and performed parameter optimization. The results showed that the optimized train cross-section reduces the overturning moment by 27.19% as compared to the original section. CHEN et al [32] examined the effect of train nose length and shape on the aerodynamic characteristics in crosswind conditions. The study found that the nose length significantly affects the pressure coefficients on the windward side of the head car and the leeward side (LWS) of the tail car. When the nose length increased from 4 to 12 m, the lateral, lift forces, and overturning moment coefficients are
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XU Ao, HUANG Feng-yi, LIU Tang-hong, XIONG Xiao-hui (2025). A novel leeward airbag for enhancing aerodynamic characteristics of a high-speed train in crosswind: The effect of installation positions. Journal of Central South University. https://doi.org/10.1007/s11771-025-6050-z
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Frequently Asked Questions
What is the main purpose of the leeward airbag in high-speed trains?
The leeward airbag is designed to enhance the aerodynamic characteristics of high-speed trains under crosswind conditions by reducing lateral force and overturning moment coefficients, thereby improving operational safety and anti-overturning performance.
Which installation position of the airbag is most effective?
The airbag located at the top of the leeward side (Model III) shows the most significant improvement, reducing the lateral force coefficient by 16.71% and the overturning moment coefficient by 23.65%.
How does the airbag affect the aerodynamic forces on the train?
The airbag changes the surface pressure distribution on the leeward side, which lowers the lateral force and overturning moment coefficients, while increasing the lift coefficient, collectively enhancing crosswind stability.
What numerical method was used in this study?
The study employed a three-dimensional steady SST k-ω two-equation turbulence model to simulate the aerodynamic characteristics of the train under crosswind.
What are the practical implications of this research?
The findings provide a reference for designing next-generation high-speed trains with improved anti-overturning performance under crosswind, potentially reducing accident risks and enhancing passenger safety.
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