| The external rearview mirror of a car is a blunt body,which has a complicated flow field in the rear wake area,which directly reflects the pressure distribution on the outer surface of the car body.When the vehicle runs,the air flow through the outer rim of the rearview mirror separates and forms a turbulent structure similar to the Carmen vortex.This structure moves along the rear view of the rearview mirror and trails a long distance,and there is a regular vortex system in the structure.Eddy current and bubbles in turbulent structures and their interactions with automobile body panels and side windows are the main causes of aerodynamic noise in rearview mirror.In view of the great influence of the traditional rearview mirror design on the aerodynamic characteristics of the automobile,based on the method of computational fluid dynamics(CFD)simulation,the aim of this paper is to design an external electronic rear view mirror of the automobile,which is more consistent with the aerodynamic design requirements while reducing the impact on the aerodynamic characteristics of the automobile.After the simulation method is established,the shape and function of snail horn are used for reference,and the design of the traditional rearview mirror is modified based on the bionics design theory.The simulation wind tunnel model of automotive electronic rearview mirror is established by Catia.The flow field and the distribution of the static pressure in the wake region of the automobile rear view mirror before and after the modification is compared with the results of CFD simulation,and the influence of the external electronic rear view mirror on the aerodynamic noise of the automobile is studied and analyzed.The simulation results show that the electronic rearview mirror has the advantage of reducing the aerodynamic noise and aerodynamic drag of the vehicle compared with the traditionalrearview mirror.The whole vehicle geometry model is created,the electronic rearview mirror and the traditional rearview mirror are assembled on the whole vehicle model respectively.The simulation results show that the aerodynamic characteristics of the whole vehicle model simulation are in agreement with the results of the separate rearview mirror model simulation.The simulation of the two models effectively proves the noise reduction effect of the automotive electronic rearview mirror.Based on the simulation experimental analysis of the SST k-Omega turbulence model,this paper studies the aerodynamic characteristics of the rear view mirror wake region,and analyses the advantages of the electronic rearview mirror compared with the traditional rearview mirror and the mechanism of its influence on the aerodynamic characteristics of the whole vehicle.The research method and conclusion of this paper not only provide theoretical reference for the acoustic and aerodynamic optimization of the electronic rearview mirror,but also have some reference value for the relevant theoretical research and engineering development. |
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