Study On Transient Aerodynamic Characteristics Of Sedan And Coach Crossing Each Other

With the increasing of vehicles running on the road, it is normal that two vehicles cross each other on the road. Most domestic researchers studying vehicle aerodynamics focus on single vehicle's steady aerodynamics and few of them have done the research of two or more vehicles running on the road. Aerodynamic characteristics affects vehicle's handling stability and safety and comfort to a great extent. The turbulent and aerodynamic interference characteristics of overtaking and crossing are complex, which will affect the vehicle aerodynamic characteristics and then affect the handling stability of vehicles. Until now most domestic experts have studied on handling stability without considering the aerodynamic interference between two vehicles, and there are no exact data of aerodynamic characteristics in this state. So this study is valuable to promote the future research of automotive technology.This paper has studied the transient aerodynamic characteristics when a car and a coach cross each other.According the aim of this study, much hard work has been taken to investigate the history of this field. And I have made a plan of study items, means, and technology etc. Then Computational Fluid Dynamics, transient means of experiment and simulation and the effect of aerodynamic force on vehicle's handling stability were introduced.In this research, a typical notchback car model and a coach model which have much data of wind tunnel test were applied. At first all the data about their wind tunnel test was collected and aerodynamic coefficients were generalized. Then we made the digital car model and coach model with the same dimension and shape as the model which were used to test in wind tunnel. And then made the clear distance of computation domain, generated grid, specified the boundary, modified the parameter, solved and acquired the computational results. Comparing with the two type results from CFD and test, little difference is found.At the beginning of the study on transient aerodynamic characteristics of two vehicles crossing each other, we did some work to simulate the transient flow field around the simplified shape vehicles crossing in tunnel. This simulation...