Wind Buffeting Noise Research And Optimization For Continuous Opening Vehicle Side-windows

In recent years, the efficient velocity of automobiles improved continuously, which lead to wind buffeting noise problem becoming more and more prominent. Solving the problem of wind buffeting noise will greatly improve the overall of the car brand and consumers desire. The car usually need to open the windows during the running process. At this moment, interaction of pressure pulsation and the air in the car cavity generates the strong buffeting noise.This high strength and low frequency noise will discomfort people a lot and thus cause a seriously bad effect on their attitude toward the comfort performance. The wind buffeting noise is closely related to the opening degree of the side-window. At present, The numerical study of the wind buffeting noise is limited to the simulation of the fixed opening.Therefore,it is quite necessary to research the wind buffeting noise of continuous opening vehicle side-windows, after that, we can find out the window opening degree which is responsible for the maximum wind buffeting noise.This paper study on the wind buffeting noise of continuous opening vehicle side-windows under the high speed condition, combined with three methods of the real vehicle road test, wind tunnel test and dynamic mesh numerical simulation.On this basis,an effective noise reduction optimization is proposed.which achieved good results. The main research contents are as follows:l.The compressibility of the fluid should be fully considered because the buffeting noise is directly related to the fluid compressibility. There fore, derived from the compressible N-S equations, deduct the weakly compressible model which is suitable for the buffeting noise of continuous opening vehicle side-windows.Proved the accuracy of weak compressible model on the buffeting noise problem by comparing the simulation results of simple compartment models with experimental results.2.Experiment a road test for a given car, select the two ears of the driver as monitoring points, study the resonance frequency and the sound level of the buffeting noise changed with different window opening degree under different velocity conditions.3.Dynamic mesh simulation technology is being used to realize the numerical calculation of the wind buffeting noise of continuous opening vehicle side-windows, The method of approximate opening equivalent substitution is proposed for the calculation of the results of acoustic post-processing. The comparison of the results of the treatment with the road test results proves the accuracy of the method.4.Find out the opening degree of the left rear window which cause maximum wind buffeting noise. By analyzing the flow field and the pressure distribution, describe the mechanism of the wind buffeting noise.5.The model of the non smooth surface of the front and rear windows is established, and using Multi-Island genetic algorithm optimize the structure parameters by multi-objective optimization which achieved good noise reduction effect.