Flow-acoustic coupling in high-speed maglev systems: Vortex-driven noise and multimodal cavity resonance under U-shaped track constraint

In recent years, the rapidity and convenience of high-speed magnetic levitation (maglev) transportation systems have attracted widespread attention. During high-speed operation of maglev trains, aerodynamic noise will become the main source of noise. The complex turbulent flow near the train body can induce intense fluctuating pressure on the train surface, resulting in broadband aerodynamic noise. This study investigates the spatiotemporal characteristics of pressure fluctuations on a maglev train operating at Mach 0.5 under U-shaped track constraint, combining wind tunnel experiment with Improved Delayed Detached Eddy Simulation (IDDES). The primary objectives are to (1) quantify the unsteady flow features driving surface pressure fluctuations, (2) validate the IDDES methodology against experimental data, and (3) identify dominant hydrodynamic mechanisms contributing to aerodynamic noise sources. The IDDES method accurately resolves the acoustic resonance phenomena in the narrow train-track channel by capturing multiscale turbulence-track interactions, with predicted cavity resonance frequencies (147 Hz, 317 Hz, 440 Hz) and vortex shedding tone (232 Hz) aligning closely with experimental measurements. The surface pressure levels exhibit errors below 2 dB, validating the method’s capability to model flow-acoustic coupling in constrained geometries. This work elucidates two noise-generation mechanisms: vortex shedding driven by shear layer instability (dominant 232 Hz tone) and multimodal cavity resonance in the train-track channel, governed by aeroacoustic feedback. The interplay between vortex dynamics and cavity resonance underpins the spectral hierarchy and energy transfer across the flow-acoustic coupling system.