Özet:

The paper established a computational model of aerodynamic noises for 3-train formation including 3 trains, 6 bogies and 2 windshields. Based on Lighthill acoustic theories, a wideband noise source model was used to recognize the aerodynamic noise source of the high-speed train. Aerodynamic pressures of the high-speed train were extracted and compared with experimental results. The change trends and values presented a good consistency, which indicated that the computational model in this paper was effective. Large Eddy Simulation (LES) and FW-H acoustic model was then used to conduct numerical simulation of aerodynamic noises of the high-speed train. Aerodynamic noise characteristics in the far field of the high-speed train were analyzed. Analyzed results showed that when the high-speed train was running at the speed of 250 km/h, main energy was concentrated within 1250-3150 Hz, and the noise was a wideband noise in the analyzed frequency. The longitudinal observation point was 25 m away from the track center line and 25 m away from the nose tip, and its sound pressure level reached the maximum value of 89.7 dBA, while the sound pressure level around six bogies reached local maximum. With the larger distance from the track center line, the sound pressure level at horizontal observation points presented a smaller attenuation. Incoming flow had a larger impact on aerodynamic noises around the train than the tail flow. The main noise sources of a high-speed train were located at nose tip and pilot of head train, the second noise source was bogies, and the third noise source was located at train connections.

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