Low-Frequency Aerodynamic Noise from a High-Speed Train

Abstract

Field measurements have been performed to investigate wayside low-frequency noise from a high-speed train. The measurements indicate that the observed low-frequency sound consists of three types of noise source mechanism. Pressure variations around the nose and tail parts of the train generated by train passing, low-frequency acoustic pressure waves aerodynamically caused by the train itself and viaduct structure-borne sound. The higher-speed region measurements show that the major formidable sound source of the low-frequency noise is attributable to aerodynamically generated unsteady noise, which is analogous to a line source. In order to understand acoustic source mechanism for the turbulent boundary layer, which is a main candidate of the line source, laboratory measurements using an axisymmetric model have been performed. The model experiment does not generate viaduct structure-borne sound. The results indicate qualitative agreement with the aeronautic noise measured in the actual field.