Prediction and analysis of flow-induced noise of a real-size high-speed train using compressible Large Eddy Simulation and vortex sound source

As technology advances, high-speed trains have become faster, and the aerodynamic noise generated by their exterior flow fields has become a critical consideration in the design process. Accurately predicting the flow-induced noise of high-speed trains requires high-resolution sound source generation in the near-field and noise propagation in the acoustic field without numerical dissipation. This necessitates the appropriate design of the grids from the point of aerodynamic noise generation and propagation in association with the length scales of the relevant components of an actual train. To address this challenge, this research study employs a three-dimensional compressible Large Eddy Simulation (LES) technique with high-resolution grids to simultaneously calculate the external flow and acoustic fields of a real-size high-speed train consisting of five cars running in open field. Further analysis is carried out to evaluate the contribution of major components, including the cap, pantograph, bogie, intercoach, and HVAC cover, which are known to be significant contributors to high-speed train flow noise. The study also employs the vortex sound source to analyze the generation mechanism of flow-induced noise for each component, providing insights for reducing aerodynamic noise.