Abstract: To characterize the distribution of aerodynamic noise produced by high-speed trains running in tunnels, a numerical simulation model for near-field aerodynamic noise in tunnel environments is established based on large eddy simulation and the acoustic perturbation equations. The relative motion between stationary trains and the surrounding environment is modeled using the moving wall method. Numerical simulations of near-field aerodynamic noise are conducted for single-and double-track tunnels at different speeds, demonstrating good agreement with field test results. The key findings are as follows: (1) Significant unsteady vortex structures form near complex geometric features such as train bogies and pantographs, leading to strong local turbulent pressure pulsations. (2) Aerodynamic noise propagates outward from these unsteady flow structures. In double-track tunnels, higher aerodynamic noise levels are observed near the haunches close to the train track. At a train speed of 400 km/h, the average sound pressure level (SPL) on the tunnel surface below the train roof is 124.5 dB, which is 1.5 dB higher than that above the train roof. In single-track tunnels, the sound energy is symmetrically distributed around the train, with similar SPL values of approximately 129 dB near the tunnel crown and haunches. (3) At different train speeds, the aerodynamic noise spectra at the haunch and arch foot measurement points exhibit similar characteristics, with higher SPLs in the 200-1 000 Hz frequency range and no distinct noise peaks. The aerodynamic noise at the tunnel arch foot is higher than that at the haunch, with more pronounced differences above 1 000 Hz.

Key words: high-speed train, tunnel, flow structures, large eddy simulation, aerodynamic noise