挡风墙距离影响高速列车气动性能LES研究

Influence of windbreak distance on the aerodynamic performance of high-speed trains by Large Eddy Simulation

  • 摘要: 挡风墙距线路中心线的距离影响着大风区高速列车的安全运行,为了明晰不同距离挡风墙对流场内涡干涉的影响和机理,基于大涡模拟及重叠网格技术,数值计算了挡风墙距线路中心线4种距离(l = 6、8、10、11 m)下的列车气动性能,分析了其周围流场特征。研究结果表明:列车在非过渡段区域运行时,4种距离下列车的侧向力系数及倾覆力矩系数随着距离的增加基本呈现先减小后增大的趋势,l = 10 m时气动力/力矩系数最小,降幅最大(对头车、中间车、尾车的侧向力系数降幅影响分别可达23%、76%、48%,倾覆力矩系数降幅分别为48%、77%、63%),且此时列车侧向力系数振幅最小,主要峰值频率集中在0 ~ 10 Hz;列车行驶至过渡段,l = 10 m时列车侧向力系数及倾覆力矩系数变化幅值也相对较小。在本文研究的4种远近不同距离下,l = 10 m时列车气动安全性较好,挡风墙的防风效果最好。但需要注意的是,列车运行至过渡段时,周围流场结构变化复杂,中间车受高速气流与列车风联合作用的影响最小,头车与尾车的气动性能波动较明显。本文研究结果可为高速铁路挡风墙建设与维护提供参考依据。

     

    Abstract: The distance of the windbreak from the centerline of the track affects the safe operation of high-speed trains in windy areas. In order to clarify the influence and mechanism of different distances of windbreaks on the vortex interference in the flow field, based on the large eddy simulation and overlapping grid, present work carried out numerical simulation of aerodynamic performances of high-speed train with four different distances of the windbreak from the centerline of the track (l = 6, 8, 10, and 11 m). The results indicate that when the high-speed train travels across the non-transition section, the lateral force coefficients and overturning moment coefficients of the train at four distances show basically a trend of decreasing and then increasing with the increase of the distance. The aerodynamic force/moment coefficients are the smallest among four situations studied, and the lateral force coefficients decrease by 23%, 76%, and 48% for the leading, middle, and end cars, respectively; the overturning moment coefficients decrease by 48%, 77%, and 63%, respectively, meanwhile the train has the smallest lateral force coefficient vibration amplitude, and the main peak frequency is concentrated in the range of 0 ~ 10 Hz. When the high-speed train passes through the transition section, the changes of lateral force coefficient and overturning moment coefficient of the train at l = 10 m are also relatively smaller. It shows that, among the four different distances, the aerodynamic safety of the train is the best at l = 10 m, as well the wind protection effect of the windbreak. However, it should be noted that when the train passes through the transition section, the surrounding flow structure undergoes complex changes. The middle car experiences the least impact from the combined effects of high-speed airflow and train-induced wind, while the aerodynamic performance fluctuations of the leading and end cars are more pronounced. The present research can be used as a reference for the construction and maintenance of windbreaks on high-speed railways.

     

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