Study on the influence of tunnel opening partition walls on the pressure wave characteristics and mitigation effects during train passage

This study employs a three-dimensional unsteady numerical simulation method based on the Reynolds-Averaged Navier-Stokes (RANS) equations and the RNG k-ε turbulence model to analyze the aerodynamic pressure wave characteristics of the CR400BF high-speed train (HST) passing through a single-tube double-track tunnel with a perforated partition wall at a speed of 300 km/h. The investigation focuses on the effects of the presence of partition openings, opening spacing, and opening diameter on pressure wave propagation within the tunnel and pressure distribution on the train surface. The results indicate that the openings in the partition wall serve as transmission channels for pressure waves, effectively attenuating the pressure amplitude in the main tunnel (Tunnel 1) while inducing pressure fluctuations in the adjacent tunnel (Tunnel 2), thereby altering the pressure distribution characteristics of both tunnels. Reducing the opening spacing or increasing the opening diameter enhances the pressure mitigation effect, but this leads to an increase in the pressure wave amplitude within the adjacent tunnel. As the opening diameter increases, the train surface exhibits certain pulsating pressure characteristics. Based on the concept of the equivalent cross-sectional area of the tunnel, a theoretical calculation model for the peak value of the initial pressure wave in a tunnel with a perforated partition was established. The numerical results show good agreement with theoretical predictions. The peak pressure on the train surface follows an exponential decay law as the equivalent tunnel cross-sectional area increases.