Numerical Simulations of Propagation of Bogie Noise in 3D Field by Duhamel’s Transformation Using Transient Solutions Calculated by 2D-FDTD Method
We applied a numerical technique to transform a two-dimensional (2D) solution to a three-dimensional (3D) solution based on Duhamel’s transformation method using the transient solution obtained by finite-difference time-domain (FDTD) simulation to calculate the propagation of bogie noise, which is the predominant noise from the lower part of a train. Different shapes of reflective barriers were used in this investigation, and the source model of bogie noise was treated as an array of incoherent line sources. To verify the 3D transformation results obtained using Duhamel’s method, we carried out an experiment using a 1/25 3D scale model of a reflective inverted-L barrier. The good agreement between the numerical and experimental results indicates that the 3D transformation technique is a useful tool for precisely predicting the sounds that propagate from incoherent line sources such as bogie noise sources. We also investigated several reflective barriers of different edge shapes and clarified the differences between the shielding effects of the barriers in both 2D and 3D transformed using Duhamel’s method.
KeywordsTransient Solution Octave Band Slab Track Noise Barrier Railway Noise
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