速度160 km/h列车通过隧道时侧向气动力变化特征

Characteristics of Lateral Aerodynamic Force Variation of 160 km/h Train Passing through Tunnels

[目的]我国某动车组以160 km/h的速度在明线运行时列车平稳性良好,但通过单线隧道时尾车出现周期性横向晃动的问题,需要对该动车组过隧道时列车气动特性进行深入研究。[方法]采用数值模拟方法,基于RNG k-ε湍流模型和滑移网格技术,建立了带有转向架的某动车组的三维可压缩瞬态仿真模型,研究了列车通过隧道时尾车表面压力变化情况;同时,在时域和频域内分析了列车侧向气动力特征的瞬态性质。[结果及结论]由于隧道壁面对空气流动的限制和列车尾绕流的作用,列车通过隧道时车体两侧存在压差并呈现出交替变化的特征,并且尾车侧向力交变特征更明显;列车所受侧向力具有低频周期性交变特点,主频约为2.2 Hz,且在尾车刚进隧道时气动效应最强,侧向力波动幅度最大;列车侧向力变化值可作为车辆横向平稳性分析的边界条件。

[Objective]At a speed of 160 km/h,a certain EMU in China exhibits good stability when running on open tracks.However,when passing through single-track tunnels,the tail car experiences periodic lateral swaying issues.Thus,it is necessary to conduct an in-depth study on the aerodynamic characteristics of the train when passing through tunnels.[Method]Using numerical simulation methods,a three-dimensional compressible transient simulation model of a certain EMU with bogies is established based on the RNG k-epsilon turbulent model and sliding mesh technology.The study focused on the variation surface pressure on the tail car when the train passes through tunnels.Simultaneously,the transient nature of the lateral aerodynamic force characteristics of the train is analyzed in both time and frequency domains.[Result&Conclusion]The research results indicate that due to the restriction of airflow by the tunnel walls and the effect of the train′s wake flow,there exists a pressure difference on both sides of the train body with aliternating characteristics when passing through tunnel.Furthermore,the alternation of lateral forces on the tail car is more pronounced.The lateral forces acting on the train exhibit low-frequency periodic alternation,with a main frequency of approximately 2.2 Hz.The aerodynamic effect is the strongest when the tail car just enters the tunnel,resulting in the largest fluctuation in lateral force amplitude.The variation in train lateral force can be used as a boundary condition for analyzing the vehicle lateral stability.