Research On Aerodynamic Characteristics And Running Safety Of High-speed Trains Under Cross-winds

The operating speed of high-speed train continues to be improved.Because of the improvement of the speed and the continuous mass reduction of the body,the aerodynamics problems of high-speed train are more and more significant.The running safety problem of high-speed train is one of the most significant problems under cross-winds.In this paper,the computational fluid dynamics and multi-body dynamics knowledge are used to analyze the running safety problems of high-speed train.The main works of this paper are as follows:1.Based on the three-dimensional,steady,incompressible Navier-Stokes equations and k-? two-equation model,the influences of the vehicle speed and the wind speed on the aerodynamic load of high speed train are studied.Then the stepwise regression method is used to obtain the optimal regression model of the binary quadratic polynomial regression equation with the vehicle speed and wind speed as the independent variables and the aerodynamic load of the head vehicle as the dependent variable.According to the regression model,the aerodynamic loads can be predited at a certain wind speed and train speed.2.A multi-body system dynamics model is established to study the influence of cross-winds on the running safety of high-speed train.Then the stepwise regression method is used to obtain the optimal regression model of the binary quadratic polynomial regression equation with the vehicle speed and wind speed as the independent variables and the head train safety indexs as the dependent variable.According to the regression model,the head train safety indexs can be predited at a certain wind speed and train speed.Finally,according to the relevant specification,the limited values of safety indexs are substituted into the regression model.The relationship curve between the wind speed and the vehicle speed under different safety indexes can be obtained.According to the relationship curve between the wind speed and the vehicle speed,the maximum allowable speed of the train can be obtained at a certain wind speed.This is the running security domain.3.In this paper,the aerodynamics model of the high-speed train passing through the curve under cross-winds is established,and the aerodynamic characteristics and operational safety performance of the high-speed train are studied.The air flow characteristics and the operational safety performance of high-speed train under different blowing modes(blowing inside of the curve track,and blowing outside of the curved track)are compared.4.In this paper,the aerodynamics model of the high-speed train passing each other under cross-wind is established,and the aerodynamic characteristics and the operational safety performance of the high-speed train are studied and are compared with those in the open air without cross-wind environment.