Flow modelling and noise generation of interacting prisms

Abstract

Noise generation is a significant issue for High-Speed Trains (HSTs), and as speeds increase aerodynamically generated noise becomes the dominant noise source. In this article, the effect of nose shape, carriage separation and yaw angle on the aerodynamics and noise generation are analysed using two prisms, representing a HST model. The aerodynamics are modelled using Computation Fluid Dynamics (CFD), and the flow velocity and turbulence intensity in various positions in the wake are compared with experimental hotwire data measured in the Anechoic Wind Tunnel (AWT) at The University of Adelaide, with good agreement. Finally, acoustic beamforming images of the noise generated by the interacting prisms measured in the AWT are presented. The acoustic results show that a blunt nose tends to increase noise at lower frequencies significantly, while increasing prism separation tends to increase noise over most frequencies, but most significantly at midfrequencies, and increasing yaw angle increases noise across all frequencies. Beamforming results show that at lower frequencies, this noise tends to be generated at the leading and trailing edges, while at higher frequencies the noise tends to be generated in the carriage gap.