高速列车转向架区域气动噪声源的特征识别

为了创建高速列车气动噪声源识别方法，以气动声学基本波动方程为基础，将高速列车气动声源等效为无数微球形声源组成，利用声辐射和流场物理量之间的关系，并结合高速列车气动数值仿真技术，建立了高速列车偶极子声源和四极子声源的识别方法，从全新的角度对某高速列车头车气动噪声源进行识别；基于涡声方程声源项特征，进一步揭示了偶极子声源和流场流动的关系.研究结果明确了高速列车主要偶极子和四极子声源的强弱和分布特征，表明了气流的直接撞击和分离现象是产生声源的主要原因，头车及转向架区域气动噪声源以偶极子声源为主；偶极子声源强度较大位置出现在边沿较为尖锐的地方，在绝大多数情况下流体经过时涡量急剧增加，成为其形成强声源的主要原因.

Characteristic Identification of Aerodynamic Noise Sources in High-Speed Train Bogie Area

In order to create an identification method of aerodynamic noise source of high-speed trains, based on the wave equation of aeroacoustics, the high-speed train aerodynamic sound source was equivalent to countless micro-spherical sound sources. Using the relationship between sound radiation and physical quantities of the flow field, combined with the high-speed train aerodynamic numerical simulation technology, identification methods of dipole sound source and quadrupole sound source of high-speed train were established. The aerodynamic noise sources of a high-speed train head coach were identified from a new perspective by the methods. Based on the characteristics of the sound source term of the vortex sound equation, the relationship between the dipole sound source and the flow field was revealed. The research results clarify the strength and distribution characteristics of the main dipole and quadrupole sound sources of high-speed train, and indicate that the direct impact and separation of the airflow are the main reasons for the sound sources. The aerodynamic noise sources in the head coach and bogie area are mainly dipole sound sources. The strong dipole sound sources appear at the sharp edges of the parts. In most cases, the vorticity increases sharply when the fluid passes by those sharp edges, which becomes the main reason for the formation of a strong sound source.