Analysis And Optimization Of Aerodynamic Noise For Rearview Mirror Of Passenger Vehicle Based On Fluent And Isight

The noise problem of passenger vehicle has received wide attention as people’s demands for noise in the passenger vehicle are getting higher and higher,according to relevant research,when the car is traveling at a low speed,the noise in the vehicle comes from the engine mainly,road surface,tire noise,and the aerodynamic noise component is small,when the speed is more than 80km/h,the aerodynamic noise dominates gradually,the rearview mirror protrudes from the surface of the car and contributes greatly to aerodynamic noise.Reducing aerodynamic noise can not only improve driving comfort,but also reduce fuel consumption and environmental pollution.The aerodynamic noise of rearview mirror is studied by means of simulation optimization based on CFD,the specific research contents are as follows:First,the accuracy of the steady-state calculation of the whole vehicle outflow field is verified.Referring to a type of passenger vehicle,the body point cloud is obtained from the 3D scanner,and the body point cloud is imported into UG to the 3D geometric model of the car body,the established body model is imported into the meshing software ANSYS ICEM CFD for flow field meshing and using ANSYS Fluent to calculate the flow field and the broadband noise source model is used to predict the noise distribution on the surface of the body,the noise distribution on the body surface with rearview mirror and without rearview mirror is analyzed respectively,results shows that the noise near the rearview mirror is larger,and the resistance coefficient of the body is monitored during the analysis of the body flow field,and the result of the monitoring is compared with the official resistance coefficient,and the reliability of the steady flow field of the body is verified.Then,the aerodynamic noise of the rearview mirror region is analyzed.On the basis of steady-state flow field,the large eddy simulation is used to calculate the transient state of the body and the vortices is captured in the flow field,and to place six monitoring points near the rearview mirror to monitor the noise situation in the vicinity of the rearview mirror,the transient analysis data is imported into LMS Virtual.Lab to analyze the noise spectrum of the six monitoring points.Finally,the shape of the rearview mirror is optimized.The grid model of the body with a rearview mirror is imported into the grid deformation software Sculptor for mesh deformation,in the ANSYS Fluent,the models after the grid deformation are calculated in ANSYS Fluent and LMS Virtual.Lab,and the aerodynamic drag value of the body and the noise value of the monitoring point are extracted respectively,through multi-disciplinary collaborative simulation optimization platform Isight integrated ANSYS ICEM CFD,Sculptor,ANSYS Fluent and LMS Virtual.Lab,the shape of the rearview mirror is optimized,and the optimized geometric model of the rearview mirror is obtained and its aerodynamic noise characteristics are verified.