Wind Buffeting Noise Analysis And Control For Vehicle Side-windows

In recent years, with the rapid development of domestic highwayconstruction and improvement of road condition, the effective speed ofautomobile rise consequently. For the need of ventilation or demisting, acar with windows open when rising at a high speed will generatebuffeting noise. Its high strength will discomfort people a lot and thuscause a seriously bad effect on their attitude toward the automobile’scomfort 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,based on CFD method, conducts a study on automobiles’ wind buffetingnoise character, by applying the FLUENT software. Main contents of theresearch are as follows:1. Study on simulation of automotive wind buffeting noise. Firstly,this paper model and LES model to simulate the simplified car model,and conclude the advantages and disadvantages; then, conduct theacoustics simulation with the simplified car, compare the four kinds ofsimulative data with the wind tunnel test data. The result shows that theSST-k-/LES model is more coincide with test data, thus determinewhich turbulence model for the simulation scheme.2.Study on the production mechanism of wind buffeting noise.Based on the simulation data, an analysis on the static pressure cloud isconducted in the longitudinal symmetry plane of the model at differenttimes within a resonance period. The result shows that it is the vortexwhich formed periodically at the open zone that causes the wind buffetingnoise. And through the wind buffeting research of the real vehicle, foundthat the pressure range, the airflow velocity and turbulent kinetic energyis the main factors affecting car inner wind buffeting noise,which providebasis for subsequent studies.3. Study on side windows buffeting noise of a real vehicle. Thispaper explores the characters of a real vehicle’s side windows buffetingnoise under different opening conditions. The result turns out that:(1) ifonly open one window, the buffeting noise level with the rear windowopen is obviously higher than that with the front window open;(2)if two of the windows are opened, the buffeting noise level maximizes when allthe side windows in rear row open and minimizes when all the sidewindows in front row open, and the other patterns falling in between;(3)compared to that when only one side window opens, the buffeting noiselevel is lower when different side window opens cooperated.(4) thebuffeting noise peak curve is in an irregular shape under different openingconditions, and for this paper’s several opening conditions, the conditionof side window at the same time in1/8opening is the buffeting noiseminimum condition.4. Study on measures to reduce side windows buffeting noise.Basis on the studies in the fourth chapter, this paper puts forward fourmeasures to control side windows buffeting noise, respectively areopening grooves on B column, apertures on rear mirror, spoiler on frontwindow, add columns on rear window. After simulation, the results showthat all the four methods have effect on reducing the buffeting noise, butthe fourth method is the more effect one, and the maximum degradation is15dB.