风雨环境下桥上列车气动特性及安全性研究OA

The aerodynamic characteristics and operational safety of high-speed trains running on bridges in wind and rain conditions were investigated.An aerodynamics model for the train-track-bridge system and a vehicle dynamics model were established to analyze the aerodynamic loads and surrounding flow field structure at different running speeds in both rainfree and heavy rainfall environments.The train's operational safety was evaluated using the vehicle dynamics model.The research results indicate that when a train operates in windy and rainy conditions,the aerodynamic loads on the head car have the highest magnitude and vary significantly with environmental changes.At a speed of 300 km/h,compared to rainfree conditions,the heavy rainfall environment increases the drag force by 38.76%,the lateral force by 1.99%,and the overturning moment by 1.32%.As the speed increases,the aerodynamic loads further increase.In the heavy rainfall environment,when the speed increases from 250 km/h to 350 km/h,the drag force increases by 100.97%,the lateral force increases by 33.44%,and the overturning moment increases by 18.9%.Under the influence of crosswinds,vortices form around the train,gradually moving from the lead vehicle to the rear as they move away from the body.As the speed increases,the vortex center on the downwind side moves closer to the train body.Additionally,the motion of raindrops is dominated by the flow field,and the overall distribution exhibits the characteristic of"wind-driven rain".In wind and rain conditions,the operational safety of the train significantly decreases and deteriorates further as speed increases.At a speed of 350 km/h,the maximum derailment coefficient reaches 0.78.The maximum wheelset lateral force and the maximum wheel-rail vertical force on the leeward-side wheel of a wheelset exceed their prescribed limits,reaching 64.4 kN and 185.9 kN,respectively.