Study On Side Wind Effect Of Train By Numerical Simulation

Train aerodynamics must be studied above all when running speed of train is to be improved: with the increasing of speed, interaction between train and air fluctuates violently, which causes series of aerodynamic problems that affect energy-consuming, safety, comfort and do harm to environment such as aerodynamic drag, train passing pressure pulse, side wind effect, influence towards surroundings, atomosphere noises and etc.In this thesis, on the basis of CFD(Computational Fluid Dynamics) theories, relying on strong model-building and analysis platform of FLUENT software, combined with actual project, numerical simulation is carried out to investigate railway aerodynamic characteristics under side wind.Firstly numerical simulations of 2D turbulence flow over trains with wall and without wall are performed so as to investigate mesh, turbulence model, boundary conditions and relative parameters, at the same time, through the analysis characteristics of flow field and aerodynamic forces are acquired for the train under static condition. After this, 3D models of trains with wall and without wall are built, and from the calculation results, pressure distribution, velocity gradient, path lines and aerodynamic forces of model trains in case of locomotion are analyzed and obtained. Finally SWECAST software developed by myself is employed to work out derailing coeffience, rolling coeffience and wheel -deloading ratio of trains in different cases which are used to evaluate stability of trains under different conditions. The research achievements in this thesis must have importmant referential significance and pratical useness to promote Lanxin railway project and guarantee aerodynamic stability of trains.