Anechoic wind tunnel noise tests for high-speed train bogie aerodynamic noise characterization

At speeds normally reached by high-speed trains (above 300 km/h), aerodynamic noise becomes significant. The bogie region is one of the main sources of aerodynamic noise in high-speed trains due to incoming flow impinging the bogie components and the cavity steps. Noise tests were performed in the Railway Technical Research Institute's anechoic wind tunnel placed in Tokyo, Japan, for different flow speeds from 100 km/h up to 250 km/h using simple shapes representing bogie components, and a 1:5 scale simplified bogie installed in a cavity. The noise spectra radiated by the simple shapes placed at different heights relative to the upstream cavity step are presented, showing the relation between the component geometry and position in the cavity with the produced noise. In addition, the measured noise spectra are shown for different configurations of the 1:5 scale simplified bogie: bare, only with front motor and gearbox, only with rear motor and gearbox and with all of them. The presented results aim to provide a better understanding of how the aerodynamic noise is produced in the bogie region of a high-speed train, and to be used for the prediction models adjustment or validation.