Sound source distribution of high-speed trains and reduction of aerodynamic bogie noise

Abstract

When the Shinkansen train runs at a high speed more than 300 km/h, the contribution ratio of the aerodynamic noise generated from bogies to the total wayside noise is as large as 30%. This is because the aerodynamic noise is proportional to the 6th power of the train velocity. RTRI has designed and made a large new microphone array with a diameter of 3m easy to install in the wayside of the railway. By applying the latest deconvolution algorithm to improve the spatial resolution of sound sources, it was found that the most prominent noise sources distribute around the train nose, pantographs and bogies. Because Japanese environmental standards impose to evaluate the A-weighted maximum noise level at the point 25m apart from the nearest truck after applying time-weighting, S, the aerodynamic bogie noise needs to be reduced. For this reason, we conducted a wind tunnel test to develop countermeasures to reduce aerodynamic bogie noise. As a result, several measures are found to be effective.