Aerodynamic Characteristics and Dynamic Performance of the Moving Train Under Crosswind

Abstract

The aerodynamic characteristics (research on the aerodynamic coefficients and surface pressure coefficients of trains at different wind yaw angles) and dynamic performance (research on the safety and comfort of train operation at different wind speeds and train speeds) of moving trains need to be explored to accurately evaluate their safety in a more realistic scenario. However, tests for a moving train model are costly and difficult to implement. In this paper, numerical simulations are conducted to investigate the aerodynamic characteristics and dynamic performance of moving and stationary trains. The surface pressure distribution and aerodynamic coefficients of the train are analyzed in detail. The results show that the three-component force coefficients of the stationary train are larger than those of the moving train when the wind yaw angle is less than 30°. At different train speeds and wind speeds, the running safety index based on the aerodynamic characteristics of the stationary train is larger (safer) than that of the moving train. However, the result of the comfort evaluation based on the aerodynamic characteristics of the stationary train may be too conservative. Moreover, the traditional formula is improved to more precisely predict the aerodynamic coefficients of the train within a wide range of wind yaw angles. Compared with the traditional formula, the improved formula only requires the three-component force coefficient of the vehicle at a 45° wind yaw angle, and the wind load of the train is independent of its speed. Hence, it is simpler and more convenient to calculate the wind load of the train. This work proves that it is feasible to estimate the aerodynamic force coefficients of moving trains by static wind tunnel tests combined with the improved formula.