Study On The Aerodynamic Characteristics Of High-Speed Trains

With the improving of train speed, interaction between train and air fluctuates violently, and the aerodynamic characteristics of the high-speed trains have become worse obviously. Pressure wave by high-speed trains passing and intersecting beside in open air and in tunnels is an important aerodynamic problem, and the bypassing flow field of high-speed trains changes, the aerodynamic force increases sharply, even make the trains capsized. So, it is significantly important to ensure the security of travelling by researching on the aerodynamic characteristics of the high-speed trains in different environment.Background of the research is the project of Beijing-Shanghai railway, and taking CRH high-speed train as the research object, through experiments to study the changing of pressure wave of high-speed trains passing and intersecting beside in open air and in tunnels, and the relationship between the train speed and the extent of pressure changing are obtained.According to studying the aerodynamic characteristics of the high-speed trains, the distribution of surface pressure and the external flow field characteristics of the train under different train-speed and wind-speed are obtained, through researching the aerodynamic force of train can get the relationship between the wind-train speed and the aerodynamic characteristics of the high-speed trains. The results indicate that the bypassing flow field of high-speed trains changes, the aerodynamic force increases sharply under cross-wind.Based on the installation of wind barriers is the major means to ensure the security of travelling under strong cross-wind, the aerodynamic characteristics of the high-speed trains passing wind barriers in cross-wind were simulated numerically. The distribution of surface pressure and the relationship between the external flow field characteristics of the train and the wind barriers with height are obtained, through analyzing the aerodynamic force of train under cross-wind with and without wind barriers can indicate that installation of wind barriers is able to improve the traffic safety of trains.Conclusively, the work in the thesis provides the theoretical base for promoting development of the high-speed train aerodynamic research work of our country, and results of the computational research supply the important referential values and practical purpose for the security of high-speed trains in cross-wind.