Aerodynamic Noise Characteristics of Metro Train in Tunnels at Different Speeds

Currently, the operating speed of a certain metro line’s trains in the tunnel has reached 140 km/h and is advancing toward the target of 160 km/h, making it urgent to research the aerodynamic noise of metro trains in tunnel. This paper conducts numerical simulation research on the unsteady aerodynamic characteristics and noise of the metro trains on this line operating in the tunnel at speeds of 120, 140, and 160 km/h. The study first conducts steady-state calculations on a scaled-down train based on the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) method and the Shear Stress Transport (SST) k-ω turbulence model. Subsequently, the hybrid Improved Delayed Detached Eddy Simulation (IDDES) and Acoustic Perturbation Equations (APE) method is employed to complete the aerodynamic noise calculations at different speeds. The results indicate that the flow field structures in the train connecting frame, pantograph, underbody, and wake regions are relatively complex. Pressure fluctuations are more significant in areas such as the train’s connecting frame, pantograph, coupler, the first bogie of the head car, and the bottom of the tail car driver’s cab. The acoustic pressure fluctuations are larger in the bogie regions beneath the train. The sound pressure power spectral density at six bogie monitoring points exhibits five peaks. The findings of this study can serve as a reference for the control of aerodynamic noise in the metro trains on this line and for future speed increases in metro trains.