Study on bridge tower-induced sudden wind and its impact on running performance of high-speed train

Combined with computational fluid dynamics analysis method and coupled vibration analysis method, the aerodynamic shielding effect of tower of long-span sea-crossing bridge on high-speed trains is analyzed from the aspects of flow field distribution, aerodynamic characteristics, and dynamic response. Based on k–omega shear stress transport turbulence model, a three-dimensional numerical simulation model of train-tower-girder is established. Considering the influence of bridge tower width, train speed, and crosswind speed, how the bridge tower changes the aerodynamic characteristics of the train by causing local sudden wind is discussed, and the average fluctuation amplitude (Δm) and influence width (d) are defined to quantify the tower-induced aerodynamic shielding effect. Meanwhile, the further influence of shielding effect on train dynamic response is discussed by the comprehensive wind-train-track-bridge coupled analysis system. The results show that the bridge tower greatly changes the wind environment around the train with it passes through the bridge tower area, resulting in a significant and sudden change in the aerodynamic characteristics of the train. Larger tower width and smaller yaw angle (e.g., higher train speed and lower crosswind speed) will increase the influence width and sudden change amplitude of tower-induced shielding effect on trains' aerodynamic coefficients. The further influence of tower-induced sudden wind on car body acceleration and wheel load reduction ratio of high-speed train shows a wider width than that on train aerodynamic characteristics.