Numerical Study On Aerodynamic Performance Of High-speed Maglev Train Under Sidewind

In 2006,the world’s first commercial maglev line commenced operations in Shanghai,with top speed of 430km/h.In 2016,China began developing high-speed maglev train.On June 21,2019,the high-speed maglev train with China’s own intellectual property rights has successfully run on the maglev test line at Tongji University.It marks an important new breakthrough on the development of high-speed maglev system in China.However,when the train travels at a speed of more than 500km/h,the resulting flow is compressible,and the turbulent flow field around the train is very complex,especially in the natural environment where the train is subjected to crosswind,the superposition of crosswind and speed will make the pressure distribution on the surface of the train change obviously,and the change of the flow field structure outside the train is more severe,which leads to the aerodynamic problems suffered by the train more prominent.In addition,the running mode of maglev train will make the flow field between the train and the track more complicated,which will seriously affect the suspension and orientation of the train,the running stability,and the safety and comfort of passengers.Through numerical simulation research,this thesis takes the offline 600 km/h high-speed maglev train with full-scale three groups as the study object,analyzing the aerodynamic characteristics around the train on the open wire in two conditions with or without crosswind,basing on the velocity and pressure distribution of the train surface and the flow field structure near the train body,especially the wake vortex structure,and the influence of wind direction on the aerodynamic characteristics of the train.The specific research contents are as follows:Firstly,this thesis uses the three-dimensional steady compressible flow N-S equation and SST k-ω turbulence model,and the finite volume method for space discretization,the flow model around the open line of 600 km/h high speed maglev train is established.The accuracy and reliability of the selection of software,the mesh division method and the numerical method are verified by comparing the lift coefficient and drag coefficient with the wind tunnel test data.Secondly,in order to simulate the the real ground situation as closely as possible,reduce the simulation error,and ensure accuracy of the simulation,the effect of ground effect is eliminated in this paper.And the effect of ground effect is eliminated in all simulations.Finally,by conducting numerical simulation of the external flow around the 600 km/h maglev train on the open wire of stable operation and sidewind environment,analyzes the external flow field structure and aerodynamic characteristics of maglev train,and researches the law of train aerodynamic performance with wind direction variation,keeping the train speed and the natural wind speed constant,just changing the direction of the wind direction.In this thesis,the aerodynamic performance of the high-speed maglev train is numerically simulated,the flow field structure around the train and the key area is analyzed emphatically,and the influence of the train outflow field characteristics on the aerodynamic performance of the train is obtained.The research has certain engineering practical significance and application value.