Field Test and Numerical Investigation of Tunnel Aerodynamic Effect Induced by High-Speed Trains Running at Higher Speeds

After decades of research in the field of high-speed railway technique, technology of running high-speed trains at the velocity level of 350 km/h gradually become mature. It is of great importance to capture the variation regular of aerodynamic parameters in the situation that the high-speed train runs at a higher speed level. The present paper is motivated by this knowledge gap, both field tests and numerical simulations were conducted to help illustrate the basic characteristic of transient pressure loads, micro-pressure wave, as well as the wave propagation inside the tunnel regrading train’s passage and intersection. Results present the major findings as: (1) Transient pressure loads acting at tunnel surface and train body unevenly distributes along the longitudinal, transverse, and vertical directions. Pressure peak along the longitudinal direction occurs nearly at tunnel center and fast decreases from the radiated center to the remote positions. (2) Variation of pressure peak near the tunnel portal in the situation of train’s passage and intersection is limited while its value becomes doubled at the intersection location. Field measurements suggest the maximum pressure load acting at tunnel sidewall at xtin = 200 m and tunnel center being 4.29 and 5.63 kPa, respectively; (3) The maximum value of micro-pressure wave (namely MPW) detected in the field test is approximately 36.73 Pa. Amplitude of MPW at tunnel portal is inversely proportional to its attenuated distance. Through data fitting, an empirical prediction model was established. Outcomes of this paper is anticipated to improve the understanding of tunnel aerodynamic effect regarding higher speed level and its associated problems. Besides, findings of this paper are useful for the future tunnel design.