The Dynamic Characteristics Analysis Of High-speed Train Running In The Open Air

With the development of high speed railway industry and train accelerated,it also faces a series of problems such as the resistance of train and running stability,so people pay more and more attention to aerodynamic problems related to train operation. There are many factors that can affect the aerodynamic characteristics of the train,such as the length of train, running speed and body shape, etc.Current research on the train aerodynamic characteristics has two methods,it mainly include real vehicle test and numerical simulation.This article adopts the method of numerical simulation to analyze the train aerodynamic characteristics which the train running under open air with the speed of350km/h. Especially the bogie area to the influence of the air resistance of the vehicle. Mainly includes the pressure distribution of the train, flow field around the train and the train aerodynamic drag.According to the characteristics of the flow in the flow field of this paper,using unsteady, three-dimensional, incompressible and choose RNG k-εmodel to simulate the flow field of the high speed train.The train model contains three marshalling train and complex bogie.using fluid analysis software SC/Tetra which based on the finite volume method to analyze the aerodynamic characteristics of train running under the open air. Compare to the two conditions of train aerodynamic characteristics which under350km/h,the research mainly includes:1. The surface pressure distribution of the train head, middle and tail and bogie area.2. The air flow around the train body and bogie.3. The air resistance of train body and bogie area,the air resistance of each part impact on the body. The research shows that:1.The the bogie has a little influence on the surface pressure distribution of train,surface pressure increases with the increase of the speed of the train.2. Bogie structure is complex,the air flow in the bogie area is very irregular and produce much eddy current which increases the train resistance and affects the operation stability.3. The pressure drag accounted for a large proportion of train air resistance;of the train air resistance,the air resistance of first car is the largest,at the same time,the the train air resistance of bogie part also can’t be allowed to ignore, it’s up to28.3%of the whole vehicle air resistance,train bogie in the head is the largest of all the bogies,9.8%of the whole vehicle air resistance.The data and conclusions obtained in this paper provide a reference for train resistance reduction optimization, research on the vehicle aerodynamic characteristics were added.