横风下列车平顺化对气动特性的影响  

Effect of train smoothing on the aerodynamic characteristic under crosswind

作　　者：梁习锋[1] 邹涌 刘宏康 LIANG Xifeng;ZOU Yong;LIU Hongkang(School of Traffic&Transportation Engineering,Central South University,Changsha 410075,China)

机构地区：[1]中南大学交通运输工程学院,湖南长沙410075

出　　处：《铁道科学与工程学报》2022年第9期2498-2506,共9页Journal of Railway Science and Engineering

基　　金：国家自然科学基金青年计划资助项目(11902367);国家重点研发计划资助项目(2016YFB1200504)。

摘　　要：由于横风下运行的高速列车气动特性恶化,面临侧翻的风险,并且转向架和风挡对高速列车周围的流场及气动特性影响较大,会加剧横风下的不稳定性,采用改进的延迟分离涡模拟(IDDES)方法研究横风作用下转向架和风挡的平顺化设计对高速列车气动特性的影响。研究结果表明,在横风下平顺化列车模型由于结构简单,气动阻力更小,同时由于背风侧大尺度涡流引起的负表面压力,侧向力更大,而在原始模型中转向架减弱了大尺度涡流对高速列车背风面表面压力的影响。转向架在列车底部产生了大量的旋涡,是原始模型和平顺化模型中流场出现差异的主要原因,风挡结构比转向架简单,对流场的扰动效果弱,但风挡表面压力对气动阻力会产生较大影响。在频谱分析中,由于原始模型中转向架引起的扰动,高速列车气动力震荡的幅值更大。转向架产生的大量小尺度涡与大尺度涡相互作用并削弱了大尺度涡对高速列车的影响,从而导致原始模型中气动力的主频率消失。此外,转向架产生的小尺度涡加剧了流动的混乱程度,这些涡在横风作用下被推离车体,影响测点处列车风分布,在阵风分析中导致各次运行间差异较大。原始模型中列车风的峰值出现在车头部分的轨道高度处,会对轨道旁的设备和施工人员产生威胁。High-speed trains(HSTs)under crosswinds willsuffer deterioration of aerodynamic characteristics and higher risk of overturning,in which bogies and windshields can pose great influence on flow fields and aerodynamic characteristics of the train,even enhancing the crosswind instability.In this paper,the improve delayed detached eddy simulation(IDDES)method was employed to study the effect of smoothing design for bogies and windshields on the aerodynamic characteristics of HSTs under crosswind.The results are drawn as follows.The smoothing design can remarkably reduce the drag due to the simplified structure.Meanwhile,the side force under crosswind is enlarged by the negative surface pressure caused by large-scale vortices on the leeward side,while the amplitude of the pressure is weakened by bogies in the primitive model.Extensive vortices are generated by the bogies at the bottom of the train,which is the main reason for the difference of flow field.The windshields with simpler structure cause weaker disturbance on the flow field but the windshield surface pressure have a great impact on the aerodynamic resistance.In the spectral analysis,the amplitude of aerodynamic force oscillation is much larger due to great disturbances caused by bogies in the primitive model.However,the dominant frequencies of aerodynamic forces disappear in the primitive model because tremendous small-scale vortices induced by bogies interact with the large-scale size vortices,further leading to the attenuation of the unfavorable effect of large-scale vortices on the aerodynamic forces.Besides,the induced small-scale vortices aggravating the chaos of flow are driven towards the leeward side by the crosswinds and finally change the distribution of slipstream.It can result in larger run-to-run variance in gust analysis.At the trackside height,the highest peak of slipstream emerges behind the head of train,which is hazardous to infrastructure and workers nearby.

关 键 词：平顺化设计 转向架 横风 列车风 列车空气动力学。 

分 类 号：U270.33[机械工程—车辆工程]