侧风作用下动力集中型动车组运行模式对气动特性与运行安全性的影响OA

In order to examine different operating modes that affected the aerodynamic behavior and operational safety of powered centralized trains under crosswind conditions,numerical simulations were performed to evaluate aerodynamic loads,surface pressure,and flow structures for trains running on windward and leeward tracks atop a 10 m-high embankment.The simulations were based on unsteady Reynolds-averaged Navier-Stokes equations with the realizable k-ε turbulence model.Train stability under crosswinds was assessed using critical wind speeds derived from the three mass model.The analysis compares three operating modes,i.e.,rear-push,front-pull and multiple unit configurations,and the track position influences aerodynamic response and safety were evaluated.Based on these results,practical operating strategies were proposed for railway sections exposed to strong winds.The results show that the leading vehicle on the leeward track experiences larger rolling moments than that on the windward track,resulting in reduced safety.Critical wind speeds decrease by 16.5%and 15.2%for two short-formation modes(rear-push and front-pull-configurations),while the reduction is only 3.5%for the multiple-unit mode.Among the operating modes,the rear-push configuration exhibits the lowest safety margin,whereas the multiple-unit configuration performs best.For short train formations,operating with a rear-push mode on the windward track and a front-pull mode on the leeward track improves safety by approximately 16.5%relative to the opposite arrangement.Where feasible,adopting a coupled multiple-unit operation can furtherly enhance safety by about 24.2%.