横风下高速列车的非定常气动特性及安全性

Unsteady Aerodynamic Characteristics and Safety of High-speed Trains under Crosswinds

为研究横风下不同路况(平地、路堤、桥梁)运行时的高速列车非定常气动特性及安全性,基于空气动力学和多体系统动力学理论,建立高速列车空气动力学模型和车辆系统动力学模型。采用分离涡模拟(Detached eddy simulation,DES)方法,计算在横风下运行速度为300 km/h列车的周围流场,风速为17.1 m/s,风向与列车运行方向垂直,得到各路况运行时高速列车车体所受非定常气动力的时域特性、频域特性及列车周围非定常流动结构。根据高速列车整车试验规范,以脱轨系数、轮重减载率、轮轴横向力和轮轨垂向力为安全性指标,分析不同路况下列车的运行安全性。结果表明,横风中列车所受气动载荷存在明显的非定常性,各车辆的气动载荷功率谱密度存在明显峰值,气动载荷主频集中在5 Hz以内;复线路堤背风侧运行列车的安全性最差,其次为复线桥梁迎风侧、复线桥梁背风侧、复线路堤迎风侧、平地。

In order to study the unsteady aerodynamic characteristics and safety of high-speed trains running in different road conditions（ground, embankment, viaduct） under crosswinds, an aerodynamic model and a vehicle system dynamic model of the high-speed trains are established based on the theories of aerodynamics and multi-body system dynamics.Using Detached Eddy Simulation method, the flow fields around high-speed trains with the running speed of 300 km/h under crosswinds are simulated, the wind speeds are 17.1 m/s, and the directions of winds are vertical to the running directions of trains. The characteristics of the unsteady aerodynamic forces acting on the trains in different road conditions are presented from the numerical results, which include the characteristics of the time domain, the frequency domain, and the unsteady flow structures around the trains. Then, according to the standard of testing of high-speed electric multiple unit on completion of construction, the operational safety of trains running in different road conditions are analyzed using the operational safety indicators of the derailment coefficient, the load reduction rate, the axle lateral force, and the wheel-rail vertical force. The results show that the aerodynamic loads on trains under crosswinds have strong unsteady characteristics and the power spectrum densities of the aerodynamic loads of each vehicle have obvious peak values. The dominant frequencies of the aerodynamic loads concentrated within 5 Hz. The safety of the train running in the leeward of double-track embankment is worst, followed by the windward of double-track viaduct, the leeward of double-track viaduct, the windward of double-track embankment, ground.