Influence of double-track embankment height on aerodynamic performance of high-speed train under crosswind

Models for embankments with different heights and a specific type of electric multiple units (EMUs) with three vehicles, including a locomotive, an ordinary vehicle, and a caboose, were established with the help of Creo and Fluent to simulate the operation of a train at the speeds of 300 and 350 km·h^-1 under the crosswind speeds of 17.10, 20.70, 24.40 and 28.40 m·s^-1, respectively. The obtained aerodynamic loads of the high-speed train were subsequently applied to the dynamics model established using the Simpack to calculate the dynamics performance parameters. The pressure distributions, airflow field structures, aerodynamic forces and wind-induced safeties of the high-speed train running on the leeward side of a double-track were analyzed under different embankment heights in a crosswind environment. Considerable attention was also given to the safety of the locomotive under different operating speeds and crosswind speeds. Analysis results indicate that for the same vehicle speed and crosswind environment, as the embankment height increases, the lateral force acting on the train increases overall, and the caboose experiences an opposite lateral force under crosswinds. The locomotive is subjected to the largest lateral force, while the lift increases continuously. The ordinary vehicle is subjected to a relatively large lift, and the caboose is subjected to the greatest resistance. The pressure peak of the train in a crosswind environment is at the nose tip of the locomotive and offset to the windward side. The airflow field structure remains basically the same regardless of the embankment height. There are obvious eddy currents on the leeward side of the locomotive and the bottom bogie. However, the eddy currents at the caboose are observed on the windward side. They may be the main factor causing an opposite force acting on the caboose. As the embankment height and crosswind speed increase, the derailment coefficient, wheel axle lateral force, wheel rail vertical force and wheel load reduction rate also increase, and the wheel rail vertical force is always within the safety limit. To ensure the safety of the train under the crosswind speeds of 24.40 and 28.40 m·s^-1, the speed of the high-speed train should be lower than 350 and 300 km·h^-1, respectively. 2 tabs, 21 figs, 32 refs.