Simulation Analysis Of Aerodynamics Of Vehicles Meeting Based On CFD

With the development of economy and the national energy-saving regulations increasingly perfect,automotive aerodynamics has been the state and enterprises attach importance to,in the process of driving cars in aerodynamic characteristics has become an important factor affecting the driving stability and safety.Most of the domestic focus on driving process and train crossing process in cycling,research on automobile meeting state is less and less,and the turbulence characteristics of vehicles meeting in the process of interference is very complex,the pneumatic pressure transient change,cause the car drag and side force changed a lot,which will greatly affect the stability of the vehicle and in the process of driving safety.With high speed and high speed overtaking a great relationship in the annual meeting of China's highway collision accidents,brought great losses to the country and people's life and property.So the research of vehicle crossing process gas is very important dynamic characteristics.This paper will use overlapping grid in CFD technology and grid technology to simulate the transient variation of the state of meeting,the meeting process.This article from the car aerodynamic angle,on the basis of previous studies,using numerical simulation method,the mechanism between the influence of transverse spacing,the speed of transient crossing process parameters on the dynamic characteristics of vehicle crossing process gas and vehicle aerodynamic interference.The use of advanced grid technology simulation of two-dimensional transient numerical meeting process,simulated 3 different speeds and 3 different lateral spacing meeting conditions.The purpose of the study is to analysis of the change of two vehicles during the passing process around the flow field and aerodynamic force,summed up the influence of the process of meeting the two car transient aerodynamic characteristics,so as to provide reference for the driver in the process of meeting proper operation,this research can provide reference for the construction of the theory of the road traffic safety system and national levels.From the optimization point of cycling to illustrate SUV models selected in this meeting,from the beginning of the model geometry cleanup to mesh,mesh optimization,calculation model and meshing domain,and then to the model partition,setting boundary conditions,the selection of physical model,the boundary layer set a series of treatment plan optimization the air dynamics,calculate the drag coefficient,and then through the optimization combination,also calculate the numerical optimization scheme to obtain the optimal portfolio drag system,the resistance coefficient Cd=0.323 final.Using Gambit to establish the vehicle model and grid division,the definition of the import and export of boundary conditions and wall conditions,into Fluent simulation,according to simulation results,the application of computational fluid dynamics(CFD)dynamic mesh technology in analysis because the basin boundary caused by the movement of flow model motion state changes with a change of variables.Combined with the principle of pressure contours,velocity vector diagram,turbulent kinetic energy and dynamic changes of air flow.The driving on the highway and highway three on the different velocity and distance of oncoming cars crossing the transient aerodynamic characteristics simulation research on combination of new highway engineering construction standard.According to the simulation results and the change of the lateral force,the influence of speed and spacing on the stability of the vehicle is analyzed.The results show that the vehicle lateral force with different distance and speed change curve of unstable wave,lateral force will have negative or positive changes at a specific speed and specific space.The air force will have an important impact on the state of vehicle handling and stability.