| With the rapid development of high-speed trains in our country,the operating speed of trains is also increased,our country has a vast territory and different line structures.There are special road conditions such as embankments,viaducts,and tunnels in high-speed railway lines.Special operating conditions under cross wind conditions have a greater impact on the aerodynamic safety of high-speed trains,most of the existing studies have compared and analyzed the differences in aerodynamic performance under special road conditions such as embankments,canyons,and tunnels.Due to the low aerodynamic safety of high-speed trains running on the leeward side of the double-track embankment in a crosswind environment,it poses a potential threat to the safety of train operation.Therefore,this article explores in detail the aerodynamic characteristics of high-speed trains running on the leeward side of the double-track embankment at different heights.Research on the dynamic performance indicators of the high-speed train leading vehicle under various embankment conditions to evaluate the operating safety of the high-speed train in a crosswind environment.Firstly,a three-dimensional model of the head,middle and tail of the high-speed train and embankment models of different heights were established to simulate the train running on the leeward side of the embankment with different crosswind speeds,operating speeds,and different heights.Analyze the train aerodynamic force,the surrounding flow field structure,surface pressure distribution,and the force conditions on the windward and leeward sides of the train,and compare the force changes of the leading vehicle,the middle vehicle and the trailing vehicle under various working conditions.Multi-body dynamics model had established with Simpack software,and apply the aerodynamic force and torque obtained by Fluent simulation to the dynamic model,focus on exploring the dynamic performance index parameters of the leading vehicle under various embankment conditions,analyze the influence of running speed,crosswind speed and embankment height on the train dynamics performance index,and compare the differences between the dynamic performance evaluation indexes.The research results show that the lateral force is the biggest factor affecting the train when the high-speed train is running in a crosswind environment.The leading vehicle receives the largest lateral force,and the trailing vehicle receives side force in the opposite direction,but the value of the side force was the smallest,with the increase of cross wind speed and running speed,the aerodynamic force received by the train shows an overall increasing trend,and the aerodynamic force received by the train gradually increases with the increase of the height of the embankment under the same wind speed and vehicle speed.When the cross wind affects the following vehicle body surface,the pressure peak point is located at the tip of the nose of the leading vehicle and is offset by a certain distance to the windward side,and negative pressure values appear on the leeward side of the train,the roof and the bogie area.The flow field distribution structure under all operating conditions is basically the same,eddy currents are formed on the bottom of the leading and trailing vehicle,and on the leeward side of the trailing vehicle,while the vortex tends to form on the leeward side of the leader and the embankment.The formation of vortices has a greater impact on the body of the vehicle.The leading vehicle dynamics performance index also increases with the increase of the height of the embankment,and the operating safety of the high embankment is relatively lower than that of the low embankment.Among them,the wheel load reduction rate is more stringent as the evaluation standard,the derailment coefficient and the lateral force of the wheel axle are second,and the wheel load reduction rate is more stringent.The rail vertical force index has never exceeded the safety limit. |
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