Study On Aerodynamic Characteristics Of A High Speed Train Under Cross Wind

With the development of high speed railway and train speed,interaction between train and air fluctuates violently.More aerodynamic problems deteriorating running safety demand a prompt solution.This thesis combines aerodynamics to study the characteristics of wind-induced security of high speed trains on the flat ground.According to the aerodynamic problems caused by cross-wind,the CRH2 train was taken as an example in this paper,the software ICEM was used to create a grid for the existing model of the train.Based on the three-dimensional unsteady incompressible Navier-Stokes equation,k-? two equation turbulence model and LES turbulence model,the finite volume method was used to simulate the aerodynamic characteristics and pressure distribution by the large fluid analysis software Fluent,in addition,the aerodynamic characteristics of trains under crosswind conditions were also studied.Large-eddy simulation(LES)was made to solve the flow around a simplified high speed train under the influence of a cross-wind.The Reynolds number of the flow was above Re=2.5*107 based on the height of the train and the incoming air velocity.The results are obtained at a yaw angle(the angle between the relative sidewind direction and the train cruising direction)of 90°.The unsteady aerodynamic characteristics of a generic high speed train under cross winds are studied numerically by the large eddy simulation(LES)method.The numerical results indicate that the aerodynamic forces on the train have strong unsteady characteristics even when the cross wind is constant.To calculate conveniently,the simulation on trains passing under cross-wind at a yaw angle of 90° is to apply k-? two equation turbulence model for the results.The static pressure distribution of this case is the combination of the these of the case under crosswind and the trains passing case.Moreover,the aerodynamic forces on the train appear strong unsteady characteristics.