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通过三维大涡模拟(LES)数值计算方法,对横风中不同行使工况下高速列车的非定常空气动力特性进行研究。计算得到各工况下高速列车车体所受非定常空气动力的时域特性、频域特性、脉动特性,以及列车周围非定常流动结构。分析结果表明,横风中高速列车所受空气动力存在明显的非定常性。从各工况高速列车所受空气动力脉动的均方根值来看,各节车的非定常现象基本随着合成风向角的增加而增大。在高速列车所受非定常空气动力的频域特性方面,其峰值频率集中在斯托劳哈尔数0.05~0.2范围内,这一范围对应实车情况的频率为0.5 Hz~2 Hz,这与高速列车系统本身存在的一些固有振动频率接近,存在由横风引起高速列车系统共振、降低高速列车行驶安全性乃至引发高速列车脱轨倾覆的可能性。
The unsteady aerodynamic characteristics of high-speed trains under different operating conditions in cross wind were studied by using three-dimensional large eddy simulation (LES) numerical calculation method. The time-domain characteristics, frequency-domain characteristics and pulsation characteristics of unsteady aerodynamics of high-speed train body under various conditions are calculated and the unsteady flow around the train structure is obtained. The analysis results show that there is obvious unsteady aerodynamics on the high-speed trains in the crosswind. According to the rms value of aerodynamic pulsations of high-speed trains in all working conditions, the unsteady phenomena of all kinds of motor vehicles basically increase with the increase of composite wind direction angle. In terms of the frequency domain characteristics of unsteady aerodynamics experienced by high-speed trains, the peak frequencies are concentrated in the Stojulzal number range from 0.05 to 0.2, which corresponds to 0.5 Hz to 2 Hz for actual vehicle conditions, Some inherent vibration frequencies of high-speed train system itself are close to each other, which may cause resonance of high-speed train system caused by cross-wind, reduce the safety of high-speed train and lead to the possibility of derailment of high-speed train.