Rapid Simulation And Verification Of Aerodynamic Noise In Vehicle Side Window Area Based On SNGR Method

With the improvement of automotive technology and the popularization of new energy vehicles,vehicle driving noise and transmission noise have been significantly suppressed.In the meantime,the increasingly perfect national road construction has made high-speed driving a common phenomenon.In this case,the problem of vehicle aerodynamic noise has attracted the attention of more and more consumers and major automobile manufacturers.In order to save development costs,various car companies often use a combination of numerical simulation and wind tunnel tests to develop vehicle aerodynamic noise performance,the wind tunnel test is used to determine the final design scheme.It can be noticed that the numerical simulation of aerodynamic noise plays an important role in vehicle development.However,the current general aerodynamic noise simulation methods are faced with the problem that the solution period is too long due to the need to calculate the unsteady flow field outside the vehicle.Therefore,this paper adopts a stochastic noise generation and propagation method(SNGR)that only needs to solve the steady flow field to analyze the aerodynamic noise in the side window area of a certain vehicle,and then the relevant parameters of the rearview mirror of the vehicle are analyzed.Based on this,the reliability of the SNGR method is probe.The main research contents are as follows:Firstly,the vehicle shape model and wind tunnel model are established based on a real SUV,and the grids of different grid scales are divided for different regions;the appropriate physical model and related turbulence parameters are determined according to the actual working conditions,and the6)- turbulence model is used to solve the problem.According to the RANS equation,the numerical simulation results of the external flow field of the vehicle are obtained.According to the calculation results,the relevant phenomena in the external flow field are explained,and combined with the aerodynamic noise generation mechanism,the research object of this paper is the side window area.Extract the flow field calculation results,use the velocity stochastic model to diverge the steady flow field information,and simulate the unsteady flow field information.According to the final calculation frequency,the side window area is divided into acoustic meshes,and the flow field calculation results are interpolated into the sound field.On the grid,the acoustic parameters of the material and the infinite element surface are finally set to solve the sound field.According to the calculation results of the sound field and the calculation results of the external flow field,the yaw angle and section parameters of the vehicle rearview mirror are optimized respectively,and three final design schemes model-1,model-2 and model-3 are obtained by combining the optimization schemes.The aerodynamic noise is solved,and the results show that the design scheme model-3 with a yaw angle of 10° and a section parameter(6 of 140 mm has the best aerodynamic noise performance.In order to verify the reliability of the calculation results of the SNGR method used in this paper,the general aerodynamic noise simulation method was used to solve the three final design schemes respectively.The sound pressure level changes regularly,and the calculation time of the SNGR method is shorter.On this basis,the model-1 of the original design and the model-3 with more obvious optimization effect were respectively carried out in the wind tunnel test.The sound pressure level reduction of different models was found,and the SNGR method was found to be more accurate when calculating the sound pressure level reduction of different models.In summary,in the development stage of vehicle aerodynamic noise performance,the SNGR method can be used to quickly predict the aerodynamic noise performance of different optimization schemes in a relatively short period of time,and the final scheme design can be carried out in combination with experiments.