Study on Sound and Vibration Propagation Caused by External Flow Affecting Interior Noise of Railway Vehicles

Abstract

Among the aerodynamic noises generated by Railway Vehicles running at high speed, the noise generated by the structure on the roof not only affects the environment along the railroad tracks outside the vehicle, but also propagates inside the vehicle, damaging the comfort of the cabin. Exterior noise is a phenomenon in which aerodynamic noise generated by the structure propagates, and the source of the noise has been clarified and predicted. On the other hand, interior noise is a combination of flow-induced aerodynamic noise propagating acoustically and structural excitation caused by pressure fluctuation due to wake vortices around the structure, and these two phenomena have not been investigated quantitatively. In this study, the effects of aerodynamic noise generated by structures in the airflow on the acoustic environment inside and outside the vehicle were experimentally investigated using a small low-noise wind tunnel from the viewpoint of source and propagation characteristics, and practical modeling of these effects was attempted. In addition, the characteristics of the sound source were investigated in detail by computational aeroacoustic analysis.