Study on Propagation Characteristics of the Noises Radiated from Railway Vehicles

초록

The railway noises created by railway vehicles give much annoyance to residents along the railway line. One method to reduce the noise transmitted from the train is to install the noise barrier. However, it is necessary to understand propagation characteristics of the noises radiated from such sources in order to reduce the noise level more efficiently with the barrier. Noise source models for trains in Korea are proposed to analyze types of propagation characteristic for railway noise. Generally, the major noise sources for trains are wheel/rail noise, aerodynamic noise and power unit noise. In this paper, we propose point noise sources model for wheel/rail noise and power unit noise to analyze the propagation characteristic of three types of trains (Electric Multiple Unit: EMU, Conventional Train, Korean Train Express: KTX). The analysis results with the models were compared with the experimentally measured ones. It is shown that the propagation characteristic of wheel/rail noise is a dipole type and power unit noise generated by the engine and its equipment are radiated as cosine type. The noise level of a train at a receiving point with the higher speed was increased in forward direction of the train and reduced in reverse direction with Doppler Effect. The Doppler Effect was considered to study propagation characteristics of the noise sources for KTX. The analytical results with Doppler Effect applied) at 300km/h show a good agreement with the measured ones.