For high-speed trains, the aerodynamic noise becomes an essential consideration in the train design. The pantograph and pantograph recess are recognised as important sources of aerodynamic noise. This paper studies the flow characteristics and noise contributions of three typical high-speed train roof configurations, namely a cavity, a ramped cavity and a flat roof with side insulation plates. The Improved Delayed Detached-Eddy Simulation approach is used for the flow calculations and the Ffowcs Williams & Hawkings aeroacoustic analogy is used for far-field acoustic predictions. Simulations are presented for a simplified train body at 1/10 scale and 300 km/h with these three roof configurations. In each case, two simplified pantographs (one retracted and one raised) are located on the roof. Analysis of the flow fields obtained from numerical simulations clearly shows the influence of the train roof configuration on the flow behaviour, including flow separations, reattachment and vortex shedding, which are potential noise sources. A highly unsteady flow occurs downstream when the train roof has a cavity or ramped cavity due to flow separation at the cavity trailing edge, while vortical flow is generated by the side insulation plates. For the ramped cavity configuration, moderately large pressure fluctuations appear on the cavity outside walls in the upstream region due to unsteady flow from the upstream edge of the plate. The raised pantograph, roof cavity, and ramped cavity are identified as the dominant noise sources. When the retracted pantograph is located in the ramped roof cavity, its noise contribution is less important. Furthermore, the insulation plates also generate tonal components in the noise spectra. Of the three configurations considered, the roof cavity configuration radiates the least noise at the side receiver in terms of A-weighted level.

对于高速列车，空气动力学噪声已成为列车设计中的重要考虑因素。受电弓和受电弓凹部被认为是空气动力噪声的重要来源。本文研究了三种典型的高速火车车顶配置的流动特性和噪声贡献，即空腔，倾斜空腔和带有侧隔热板的平顶。改进的延迟分离涡流模拟方法用于流量计算，而Ffowcs Williams＆Hawkings航空声学模拟法用于远场声学预测。针对这三种车顶配置，以1/10比例和300 km / h的简化火车车身进行了仿真。在每种情况下，两个简化的缩放仪（一个缩回，一个抬起）位于屋顶上。通过数值模拟获得的流场分析清楚地表明了火车车顶配置对流动行为的影响，包括流动分离，重新附着和涡流脱落，这些都是潜在的噪声源。当列车车顶由于空腔后缘处的流动分离而在车顶具有空腔或倾斜空腔时，在下游会发生高度不稳定的流动，而侧隔热板会产生涡流。对于倾斜的腔构造，由于来自板的上游边缘的不稳定流动，在上游区域中的腔外壁上出现适度大的压力波动。凸起的缩放仪，屋顶空腔和倾斜的空腔被确定为主要噪声源。当缩回的缩放仪位于倾斜的屋顶空腔中时，其噪声贡献就不那么重要了。此外，绝缘板还在噪声频谱中产生音调分量。在考虑的三种配置中，就A加权水平而言，顶腔配置在侧面接收器处辐射的噪声最小。