Prediction And Air Jet Optimization Of Sound Quality Of Automobile Wind Buffeting Noise

Vehicle wind buffeting noise is generated due to the interaction between the air inside the vehicle and the external air flow when the window is opened during the driving.This aeroacoustic response has the characteristics of low frequency and high intensity,which is easy to cause irritability and fatigue of the driver and passengers,and seriously affects the ride comfort of the vehicle.As the trend of automobile research and develop gradually shifts from product performance to quality improvement,the research on wind buffeting noise of vehicles with sound pressure level as the single control and optimization index also needs to be extended to the sound quality research and development level.However,at present,there is still insufficient attention paid to the sound quality of wind buffeting noise in automobiles at home and abroad.Therefore,this paper makes an objective evaluation and subjective evaluation research on the sound quality of wind buffeting noise caused by the opening of the car sunroof,the right front window and the right rear window.The artificial neural network theory is introduced into the research field of sound quality of automobile wind buffeting noise for the first time.Genetic algorithm(GA)is used to optimize BP neural network algorithm to establish GA-BP sound annoyance prediction model of automobile wind buffeting noise,and objective sound annoyance evaluation index is proposed.Finally,an air jet structure is designed to optimize the objective annoyance of the wind noise noise quality of the car.The main research contents of this paper are as follows:1.Based on the acoustic theory,the LES method based on the relaxed weak compressible model is used to simulate the automobile wind buffeting noise.At the same time,the wind buffeting noise road test was carried out.The comparison between the calculation results and the test results was carried out,and the accuracy of the large eddy simulation method was verified.2.Based on the numerical simulation of wind buffeting noise of automobile,the subjective and objective evaluation of the sound quality of wind buffeting noise of automobile is studied.Eight sound quality objective evaluation parameters such as sound pressure level,peak frequency,loudness,roughness,sharpness,fluctuation,AI and speech interference level were calculated,and the variation rules of each parameter were analyzed.The grading method is used to test the subjective evaluation of sound quality of automobile wind buffeting noise.3.Eight objective parameters are used as input,and subjective sound annoyance is output.The BP neural network model is optimized by genetic algorithm,and the nonlinear mapping relationship between subjective and objective results is established.The GA-BP prediction model of automobile wind buffeting noise is obtained.An evaluation index called objective sound annoyance of sound quality of automobile wind buffeting noise is proposed.4.According to the generation mechanism of wind buffeting noise,an air jet spoiler structure is designed to optimize the sound quality of wind buffeting noise of automobile sunroof and rear right window.The air jet structure parameters were optimized to determine the optimal angle,speed and width of the jet structure.The structure can suppress the size of the falling vortex,change the running trajectory of the falling vortex,and reduce the probability of the falling vortex colliding with the rear edge of the window,thereby achieving the goal of optimizing the sound quality.