| The aerodynamic performance and operational stability of High-speed train will change significantly under the action of crosswind, and the risk of overturning or derailment will greatly increase。Therefore, it is need to further study crosswind effects of high-speed trains, so as to take effective way to ensure the operational safety and improve the stability. With the real CRH type EMUs as the object of study in this paper, their aerodynamic characteristics and operation stability are analyzed.The aerodynamic characteristics and the fluid field around the high-speed train under crosswinds are numerically simulated,by means of the CFD software STAR-CCM+, based on the 3-D, steady and incompressible Navier-Stokes equation, combined with the k-εturbulence model,for Double-track embankment and ground. Surface pressure,flow field and velocity field distribution of high-speed trains were analysised by simulation, when it is running at different speeds on different side of the embankment, and get the variation of the aerodynamic force coefficient with the increase of vehicle velocity and wind speed,that is pointed out difference of aerodynamic characteristics. Also, crosswind effects of the train were compared with ground and double-track embankment; grasp the similarities and differences between them.Combined with Vehicle and track dynamics, multi-body dynamics model of CRH were established, by means of the multi-body dynamics software SIMPACK, based on Kalker's theory of non-linear in rolling contact and the Beijing-Tianjin track spectrum.Then the loads, obtained by simulation calculating of software STAR-CCM+, were dealt with as the external loads on the train.By dynamic simulation calculating, parameters such as the coefficient of derailment, rate of wheel load reduction, the lateral force and vertical force of wheel/rail were obtained. With reference to the safe operation criteria for high-speed trains, the maximum safe running velocity of the high-speed train under different-speed cross wind is specified.This work will provide experience on the study of aerodynamic problems and stability problems when CRH type EMUs run on the Double-track embankment, also having some reference value to wind-breaking safety of high-speed railway and Stability of train. |
