Aerodynamic Effects Caused by Trains Entering Tunnels

With the increase in train speed, the aerodynamics in tunnels is emerging. In recent years, we have carried out a few full-scale tests about tunnel aerodynamics, and the law of influence of train speed on pressure change, airflow velocity, and micropressure wave are obtained, and a passenger comfort survey was conducted. When a high-speed train enters a tunnel at 200 km/h, the pressure change amplitude and pressure change per second inside the vehicle are 1,036 Pa and 273 Pa/s, respectively, and 88.9% people experienced no obvious discomfort; the airflow velocity in the tunnel is 14.8 m/s, which exceeds the criterion, 14 m/s. Therefore, it is suggested that workers should not work in the tunnel when a train passes; because the micropressure wave is only 9.7 Pa at the measured point, 20 m from the exit port of tunnel, the tunnel has a cross section enlarged hood with windows, and the passing train does not impact the environment near the tunnel.