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Mechanism and Control about Vehicle’s Wind Buffeting Noise

Author: DongGuangPing
Tutor: GuZhengQi
School: Hunan University
Course: Vehicle Engineering
Keywords: Wind buffeting noise of vehicle CFD LES Side Windows Sunroof
CLC: U461
Type: Master's thesis
Year: 2012
Downloads: 67
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Abstract

With the rapid development of domestic highway construction and improvementof road condition, the practical speed of automobile rise consequently. Meanwhile,customers’ requirement for automobile’s comfort performance, especially the interiornoise performance, also becomes more and more high. For the need of ventilation ordemisting, a car with windows open when rising at a high speed will generate highstrength buffeting noise. Although the frequency of wind buffeting noise isconsiderably low, its high strength will discomfort people a lot and thus cause a badeffect on their attitude toward the automobile’s comfort performance. Therefore, it isquite necessary to estimate, analyze and control wind buffeting noise in theautomobile’s design phase, accompanied with meaningful theoretical and practicalvalue.Due to the development of computer technology and turbulence theory, and theincomparable advantages of Computational Fluid Dynamic (CFD) method, now it’spossible to study automobile’s wind buffeting noise by using CFD method. This paper,based on CFD method, conducts a study on automobiles’ wind buffeting noisecharacter, by applying the FLUENT software and LES (Large Eddy Simulation)theory. Main contents of the research are as follows:1. Study on simulation of automotive wind buffeting noise. Before making aresearch on a real automobile, this paper first builds a simplified car model andstudies the wind buffeting noise of it by using acoustic wind tunnel test and CFDsimulation. The corresponding experimental result and simulative data show that theycoincide with each other quite well, and this proves the accuracy and reliability of theCFD method and solution setup applied in this paper.2. Study on the formation mechanism of wind buffeting noise. Based on thesimulation data, an analysis on the static pressure cloud is conducted in thelongitudinal symmetry plane of the model at different times within a resonance period.The result shows that it is the vortex which formed periodically at the open zone thatcauses the wind buffeting noise.3. Study on side windows buffeting noise of a real vehicle. This paper exploresthe characters of a real vehicle’s side windows buffeting noise under different openingconditions. The result turns out that:(1) if only one window opens, the buffeting noise level with the rear window open is obviously higher than that with the front windowopen;(2)if two of the windows are opened, the buffeting noise level maximizes whenall the side windows in rear row open and minimizes when all the side windows infront row open, and the other patterns falling in between;(3) compared to that whenonly one side window opens, the buffeting noise level is lower when different sidewindow opens cooperated. The analysis shows that the scale of the vortex formed atthe windows’ open zone is one of the key factors that influence the intensity of windbuffeting noise.4. Introduction and proposition on wind buffeting noise controlling for sidewindows. This paper introduces several effective controlling measures for the rearwindow’s buffeting noise, and also proposes a new method to control the frontwindow’s buffeting noise, which has been proved in the simulation result.5. Analysis and optimization on the vehicle’s sunroof buffeting noise. Based onthe study of the vehicle’s sunroof buffeting noise character, this paper introducesmodern optimization algorithm to the sunroof deflector’s design, and a set of optimalparameters is obtained. Finally, the result demonstrates that the maximum noisereduction rate reaching to11.1%.In conclusion, this paper conducts an intensive and systematic research on theautomotive’s wind buffeting noise characters, and all these work can providemeaningful research thinking and methodological procedure for engineeringapplication.

Mechanism and Control about Vehicle’s Wind Buffeting Noise

Abstract

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