Mechanism And Optimization About Vehicle Wind Buffeting Noise Based On The Weakly Compressible Model

In recent years, with the rapid development of national economy, thetotal mileage of highway has already ranked second in the world and theefficient velocity of automobiles improved continuously. At the sametime, the amount of automobiles is increasing rapidly, and the driver’scomfort requirements are also getting higher, which lead to windbuffeting noise problem become more and more prominent.For the needof ventilation and demisting, the car usually need to open the windowduring the running process.At this moment, interaction of pressurepulsation and the air in the car cavity generates the strong buffetingnoise.This high strength and low frequency noise will discomfort peoplea lot and thus cause a seriously bad effect on their attitude toward thecomfort performance. Therefore, it is quite necessary to estimate, analyzeand control wind buffeting noise in the automobile’s design phase,accompanied with meaningful theoretical and practical value.This paper study on the mechanism of wind buffeting noise of a carwith an opened window under the high speed condition, combined withthree methods of the real vehicle road test, wind tunnel test and numericalsimulation.On this basis,conduct the noise reduction optimization byoptimizing the window size.which achieved good results.The mainresearch contents are as follows:1. Experiment a road test for a given car, select the two ear of thedriver and two point of backseat as monitoring points, study theresonance frequency of the buffeting noise and the change low of soundlevel with car velocity of the four monitoring points under the differentconditions.2. In the process of research, the compressibility of the fluid shouldbe fully considered because the buffeting noise is directly related to thefluid compressibility. Therefore, derived from the compressible N-Sequations, deduct the weakly compressible model which is suitable forthe buffeting noise.Proved the accuracy of weak compressible model onthe buffeting noise problem by comparing the simulation results of simplecompartment models with experimental results. 3. Applying the simple carriage model to analysis the mechanism ofautomobile wind buffeting noise, analysis the reasons for the differencesof buffeting noise under the condition of crosswind and withoutcrosswind, and studied the effects of different wind velocity and angle ofthe wind vibration noise. At the same time, make a contrastive analysis tothe buffeting noise with different opening mode of sunroof and sidewindows.4. According to the generation mechanism of wind vibration noise,proposed a noise reduction additional device attached to the side window,using multi-Island genetic algorithm optimize the result parameters of thefront and back additional device which achieved good noise reductioneffect. In addition, also tried to use the riblet surface and hole denoisingmethod to control the wind buffeting noise at the side window.Meanwhile,applying the modern design method to optimize the position and lengthand width of the sunroof which achieved further control to the windbuffeting noise.On this basis, makes a contrastive study on the noisereduction effect for different shapes of the groove guiding plate.