基于非定常气动特性的高架动车组振动特性试验研究

定常横风引起的非定常气动特性影响高架运行列车的安全性和舒适性。开展定常横风下高架动车组的风洞试验，测试记录其车体表面压力时程曲线，进而分析其非定常气动特性及振动特性。试验结果表明，同一侧滑角同一风速下，车体中部同一侧测点的时程压力平均值差别不大，基本相等。当侧滑角保持90°不变时，测点气动压力的平均值、最大值和最小值与合成风速的二次方成正比；随着风速的增加，测点非定常压力波动加剧，波动幅度显著增大。当合成风风速保持60 m/s不变时，测点气动压力的平均值、最大值和最小值与侧滑角的1.27次方成正比；随着侧滑角的增大，测点的峰峰值呈现抛物线变化规律，非定常波动幅度先减小后增大。高架动车组车体的主振频率带随横风风速的增大基本保持不变，随侧滑角的增大基本保持不变；振动频率均在0～18 Hz范围内，并明显存在几个主要振动频率带，分别为8～10 Hz、0～2 Hz、14～16 Hz及16～18 Hz。

Experimental Research on Vibration Characteristics of Viaduct Operation EMU Based on Unsteady Aerodynamic Characteristics

An unsteady aerodynamic characteristics caused by steady crosswind affect the safety and comfort of viaduct operation train. The wind tunnel test of viaduct operation electric multiple units(EMU) under steady cross wind is carried out. The time-history curve of the surface pressure of the car body is tested and recorded to analyze its unsteady aerodynamic characteristics and vibration characteristics. The test results show that:under the same sideslip angle and the same wind speed, the average value of the time course pressure at the same side of car body is not much different, and is basically equal. When the sideslip angle remains unchanged at 90°, the average, maximum and minimum values of the aerodynamic pressure at the measuring point are proportional to the square of the synthetic wind speed; as the wind speed increases, the unsteady pressure fluctuations at the measuring point increase and the fluctuation amplitude is significant increase. When the synthetic wind speed is maintained at 60 m/s, the average, maximum and minimum values of the aerodynamic pressure at the measuring point are proportional to the 1.27 th power of the sideslip angle; as the sideslip angle increases, the peak-to-peak value at the measuring point appears parabolic change law, the amplitude of unsteady fluctuation first decreases and then increases. The main vibration frequency band of viaduct operation EMU coach remains unchanged with the increase of the crosswind wind speed and the same with the increase of the sideslip angle; the vibration frequency of two sides are both in the range of 0-18 Hz, and there are obviously several main vibrations frequency bands are 8-10 Hz, 0-2 Hz, 14-16 Hz and 16-18 Hz respectively.