高速列车排障器底部后端扰流对转向架区域流场与气动噪声特性的影响

Impact of Turbulent Flow underneath the Rear Snowplough on the Flow Field of Bogie Region and Aerodynamic Noise Characteristics of High-Speed Train

针对高速列车一位转向架受到来流冲击产生较强气动噪声的特点,基于声类比方法,采用安装普通排障器和底部后端设置平行凹坑排障器的高速列车转向架区域简化模型和车头比例模型,计算分析平行凹坑对转向架区域流场和气动噪声特性的影响,并进行声学风洞测试,验证数值模拟气动噪声的降噪效果。结果表明:在高速列车排障器底部后端设置凹坑,可抑制转向架区域流场剪切层的生长和发展,削弱转向架舱前缘流动分离并缓和尾流与舱内各部件的流动冲击作用,干扰转向架周围大尺度湍涡的形成和脱落,抑制排障器与转向架区域几何体表面压力脉动的形成,减少气动噪声的产生;声学风洞中列车模型排障器底部后端采用扰流措施后,转向架部位噪声源面积缩小,噪声幅值降低约1 dB(A),气动噪声得到有效控制。

Based on the characteristics of strong flow-induced noise produced from the leading bogie of highspeed train,the influence on the characteristics of flow field development and aerodynamic noise generation around the bogie through setting the parallel dents at the rear end of the regular snowplough bottom is calculated and analyzed.The proposed study is obtained through adopting a simplified model of high-speed train bogie and a nose car scale model using the delayed detached-eddy simulation model based on an acoustic analogy approach.An anechoic wind tunnel test is carried out thus verifying the noise reduction effect obtained from the numerical simulation.The results show that compared with the snowplough with smooth bottom surface,the parallel dents underneath the snowplough can mitigate the proliferation of the bogie′s shear layer and the flow interaction between the snowplough wake and the components inside the bogie cavity by producing flow disturbing.Consequently,the forming and the shedding of the large-scale vortices around the bogie structure are restrained and the aerodynamic noise produced by the wall pressure fluctuations is reduced through weakening the flow separation.The area of sound source generated from the bogie region of a scaled nose car model in the anechoic wind tunnel is reduced with the sound amplitude dropping to around 1 dB(A).Thus,the aerodynamic noise is controlled effectively.