风障表面的高速列车风致空气脉动压力研究

Investigation into Windbreak Surface Air Fluctuating Pressure Caused by High-Speed Train-Induced Wind

高速铁路挡风风障在保障高速列车运行安全的同时,本身亦承受着强烈的列车风致脉动压力荷载.基于STAR-CCM+软件,以CRH3型高速列车和挡风风障为研究对象,结合能够有效减少开孔薄板网格数量的多孔介质模型以及运动体滑移网格方法,对高速列车通过风障区域的整个过程中列车风致脉动压力的变化进行了数值模拟,分析了风障脉动压力随列车车速和离地高度等参量而改变的时程变化规律,给出了风障位置的脉动压力峰值与压力梯度,得到了列车风致脉动压力的频域特性.结果表明:高速列车通过风障区域时在风障各部位均形成了"正-负-负-正"的交变荷载,且其峰值按照头车正压、头车负压、尾车负压、尾车正压的顺序依次减小,脉动压力梯度随速度增加更加明显;风致脉动压力随高度增加而减小,最大压力出现在风障的底部区域;列车风致脉动压力的功率谱密度峰值集中在25 Hz以内,车速每增加50 km/h,列车风冲击能量增大将近一倍.

When high-speed trains are running, the windbreak can guarantee their safety. And meanwhile, it has to suffer strong air fluctuating pressure caused by the high-speed train-induced wind. In this paper, based on the STAR-CCM ＋ software and by taking the CRH3 high-speed train and the windbreak as the research objects, the change of the air fluctuating pressure caused by the train-induced wind during the whole process of the high-speed train passing through the windbreak area is simulated by combining the sliding mesh method and the porous medium model that can effectively reduce the amount of grids in hole plates. Then, the time history changes of the air fluc- tuating pressure with such parameters as the train speed and the terrain clearance are analyzed, and the peak and gradient of the fluctuating pressure in the position of the windbreak are put forward, thus obtaining the frequency domain characteristics of the fluctuating pressure. The results show that （ 1 ） when the high-speed train passes through the windbreak area, the alternating loads, which are positive-negative-negative-positive, form on each part of the windbreak; （2） the fluctuating pressure peak decreases in the order of the positive pressure on the head train, the negative pressure on the head train, the negative pressure on the tail train and the positive pressure on the tail train, and the fluctuating pressure gradient becomes more obvious with the increase of the train speed; （3） as the terrain clearance decreases, the fluctuating pressure increases and reaches up to a maximum value in the bottom area of the windbreak; and （4） the power spectrum density peaks of the fluctuating pressure are con- centrated below 25 Hz, and the impact energy of the train-induced wind increases by nearly 100% when the train speed increases by 50 km/h.