Numerical simulation of aerodynamic noise generated by high speed trains

Aerodynamic noise becomes more and more significant and sometimes could be predominant as the running speed of high speed trains increases. As a result, aerodynamic noise has to be taken into consideration during the design of high speed trains. In present work, the research on aerodynamic noise of the high speed train with a speed of 300 km/h has been performed. The nonlinear acoustics solver (NLAS) approach is adopted to study the aerodynamic noise in the near field of the high speed train. With the use of an acoustic surface, the research on the aerodynamic noise in the far field has been carried out by solving the Ffowcs-Williams/Hawking (FW-H) equation. At first the method validation is performed through a two-dimensional backward step case, which shows excellent agreement with experimental results. The characteristics of the flow field dominate the generation of aerodynamic noise, therefore the flow field is firstly analyzed, including the head, the rear, and the inter-coach spacing of the train. By use of probes in specific regions on the surface of the train, the contribution of different parts of the train to the aerodynamic noise is discussed. Meanwhile, the far field feature of aerodynamic noise is also studied by placing probes in the far field. Based on the above analysis, the aerodynamic noise performance of the specific high speed train is assessed.