Abstract
This paper established a computational model for the aerodynamic noise of a high-speed train with 3-train formation including 3 bodies, 6 bogies, 2 windshields and 1 pantograph system. Based on Lighthill acoustic theory, this paper adopted large eddy simulation (LES) and FW-H model to conduct numerical simulation for the aerodynamic noise of high-speed trains and analyzed the distribution of aerodynamic flow behavior and noises of the whole train. Researched results showed that the main aerodynamic noise sources of high-speed trains were in pantograph, pantograph region, streamlined region of head train, bogies, bogie region, windshield region, air conditioning and other regions. Pantograph head, junction of upper arm and lower arm, and chassis region were main aerodynamic noise sources of pantograph. Compared with other 5 bogies, bogie at the first end of head train was main aerodynamic noise source. In addition, vortex shedding and fluid separation were main reasons for the aerodynamic noise of high-speed trains. When the high-speed train ran at the speed of 300 km/h and 400 km/h, the main energy of the whole train focused on the range of 1000 Hz-4000 Hz. Aerodynamic noises were broadband noises in the analyzed frequency domain. At the longitudinal observation point which was 25 m away from the center line of track and 25 m away from the nose tip of head train, the total noise sound pressure level reached up to maximum values 96.5 dBA and 101.4 dBA, respectively. Compared with inflow, wake flow had a greater influence on the aerodynamic noise around high-speed trains. The main radiation direction of pantograph aerodynamic noises was the left and right sides of pantograph head. In addition, the main radiation energy of pantograph aerodynamic noises was in mid-high frequency. In the part of high frequency, pantograph head made the greatest contribution to aerodynamic noises in the far field.
Highlights
With the constant development of high-speed trains, the noise problem of high-speed trains becomes increasingly prominent
The main aerodynamic noise source of pantograph was mainly distributed in pantograph head, junction of upper arm and lower arm and chassis area
2) Through conducting a comparative analysis on the total sound pressure level of observation points (25 m away from the center line of track and 3.5 m from the rail surface) of high-speed trains, this paper found that the total sound pressure level of observation point which was 12 m away from the nose tip of head car was the maximum
Summary
With the constant development of high-speed trains, the noise problem of high-speed trains becomes increasingly prominent. Yan [10] built a computational model including head train, middle train and tail train and computed noise source intensity and far-field noises at the surface of body. Zhang [12] built an aerodynamic model including head train, middle train and tail train, computed the near-field and far-field aerodynamic noise of high-speed trains and only took into account noise sources at the surface of body instead of bogies and pantograph. Sun [13] established the aerodynamic model of 3-train formation, conducted an analysis on the flow field characteristics of train head, junction and tail, and studied the contribution of different parts of body to aerodynamic noises. Only the structure surface of body is taken as aerodynamic noise source and pantograph and bogie [20,21,22] as main aerodynamic noise sources of high-speed trains are neglected. Of head train, middle train, tail train, 6 bogies, 3 air conditioning, 1 pantograph area and 1 pantograph, and obtained the aerodynamic flow behavior of high-speed train, the distribution of aerodynamic noises of trains, the propagation characteristics of pantograph aerodynamic noises and so on
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