| As the global average temperature has risen year after year,the probability of occurrence of severe weather and climate has increased greatly.The number of urban disasters has also increased significantly.Extreme weather events such as high winds,heavy rains and high temperatures frequently occur,causing crop damage,house collapse,and rail transit traffic.It even causes major accidents such as overturning.In urban areas,urban rail transit traffic safety issues have become increasingly prominent.This paper mainly studies the influence of crosswind on the traffic safety of rail transit trains,and uses the Shanghai Meteorological Administration to assess the risk of urban wind hazards,the practical application of comprehensive engineering and meteorological data analysis,and provide reference for the optimization of the head and the aerodynamic performance of rail transit trains.The main work of this paper includes the following aspects:(1)Analyze the crosswind effect of the railroad train body under complex wind conditions.The numerical CFD calculation is used as the research method to study the aerodynamic characteristics and parameter sensitivity of the vehicle body.The variation law of the vehicle body aerodynamic force with wind angle of attack,wind speed and vehicle speed is systematically investigated.Based on this,the mechanical properties of the train are analyzed.The results show that the aerodynamic lift,lateral aerodynamic force and overturning moment are similarly affected by wind speed.The aerodynamic condition of the head car during crosswind operation is the least,and the aerodynamic force has a higher sensitivity to changes in wind direction.The influence of wind speed on the aerodynamic force of the rail transit train is greater than the speed of the vehicle.(2)Through the rail-to-rail trains entering and leaving the tunnel and the aerodynamic coefficients of the first,middle and tail vehicles at the intersection of the two vehicles,the operation of the rail-crossing trains in the tunnel is systematically analyzed.Evaluate the safety of the car body in the tunnel.The results show that the two parts of the rail-to-rail train are affected by the aerodynamic forces,especially the aerodynamic performance of the tail car when the bicycle enters and exits the tunnel.When the two cars meet in the tunnel,almost all the aerodynamic laws show the opposite sex.(3)Taking the demand of safe driving service of Shanghai Urban Rail Transit Line 16 as the starting point,the safe driving model of rail transit vehicles under crosswind environment is established by CFD numerical simulation and mechanical analysis,and various influencing factors are analyzed to safely drive vehicles.The impact of speed provides theoretical and technical support for the safe operation of urban traffic.The simulation results show that the TMC1 car near the windward side is most affected by the crosswind during the operation of the rail transit vehicle.Under the same conditions,when the derailment coefficient is used as the safety travel speed evaluation standard for rail transit trains,more design safety space is left.(4)Study the shape optimization problem of rail transit trains.The head-to-rail design specification is used to formulate the head shapes of different aspect ratios and aspect ratios.The CFD numerical simulation method is used to compare the aerodynamic performance of the vehicle body corresponding to these working conditions,and analyze the influence of the shape of the head on the aerodynamic force.Optimize the head plan of the rail transit train.The conclusion shows that the aerodynamic lift coefficient of working condition three is the four working conditions,and the working condition four is the ideal streamlined solution,which is the best solution to meet the safe driving requirements. |
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