Research On Aerodynamic Characteristic For EMU Passing By Windbreak Wall Gap Under Crosswind

West in our country every year because of the train tumbling accidents there lead to huge financial losses and casualties,so built the windbreak wall along the railway and set transition gap in the middle of the windbreak,convenient for the workers to maintenance.However,the crosswind through the gap will make serious harm to the high-speed EMU.When the EMU(Electric Multiple Units)is passing by the windbreak wall gap,the crosswind strikes at its surface,causing the aerodynamic performance exceed the standards.Therefore,the study on this problem is particularly important.Base on the basic control equations of three dimensional,incompressible,unsteady,viscous flow,standard k-? equation as well as dynamic grid technology,use numerical analysis method to study the aerodynamic characteristics of the EMU passing by the windbreak wall gap.The main research contents are list as follows:(1)According to the actual situation that the high speed train run in LanXin high speed railway,the computational model of five cars are built which passing by the windbreak wall gap.(2)In the different crosswind conditions(constant and logarithmic distribution),taking numerical analysis on the aerodynamic characteristics that 160km/h EMU running through windbreak wall gap,obtain pressure distribution law of each car body surface and the change law of the aerodynamic coefficient.(3)The aerodynamic characteristics of 200km/h EMU running through windbreak wall gap are taken numerical analysis under no crosswind and 25m/s crosswind conditions,get pressure distribution law of each car body surface and the change law of the aerodynamic coefficient,as well as the velocity distribution of the flow field around the head car in the gap.(4)The aerodynamic characteristics that 250km/h EMU running through windbreak wall gap are taken numerical analysis under 20m/s crosswind condition,gain the pressure distribution law of the nose tip and the change law of the aerodynamic coefficient.The results show that:(1)The aerodynamic coefficient of each car body reaches to the maximum when the EMU is passing by the gap.(2)The aerodynamic coefficient of the head car is maximum when the EMU passing by the gap under three conditions,the cross force coefficient are 0.3151,0.1488,and 0.1148 respectively,and the overturning moment coefficient are 0.1458,0.0718,0.0503 respectively,so the safety of the head car is the worst.The researches which have done in this paper make important guiding significance for the high-speed EMU,and provide reliable references for aerodynamic research.