Experimental investigation of an aeroacoustic feedback mechanism on a two-dimensional side mirror model

Werner, Maximilian; Würz, W.; Krämer, Ewald

doi:10.1016/j.jsv.2016.10.012

Cited by 5 publications

(2 citation statements)

References 40 publications

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“…Door panel is a specific thin-shell structure, so it can easily generate vibration and thus radiate noises into the vehicle, which would seriously affect riding comfort of people in the vehicle. It is shown in studied results that the sound pressure level increased by about 2.5 dB when the vehicle running speed increased by 10 km/h, namely aerodynamic noises excited by the rear view mirror is roughly in direct ratio to 6th power of the vehicle speed [9][10][11]. Therefore, researches on external flow fields and aerodynamic noise mechanisms caused by rear view mirrors and A pillars is very important for vehicles.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation on the impact of the bionic structure on aerodynamic noises of sidewindow regions in vehicles

Liu¹,

Li²,

Ding³

2018

J. vibroeng.

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The paper adopted a bionic hemispherical convex structure in the A pillar-rear view mirror regions according to actual requirements. Furthermore, impacts of the bionic structure on aerodynamic characteristics and noises in the region were studied. Friction resistance of airflows was greatly reduced, fluctuations and pulsation pressures of flow fields were also reduced, and characteristics of flow fields and sound fields were improved. The computational results were finally verified by the experimental test. Firstly, the aerodynamic lift force coefficient and drag force coefficient of the bionic model were computed, and they were obviously lower than those of the original model. The adhesive force between tires and ground during vehicle running was increased, and the danger degree of "waving" of high-speed vehicle running was weakened. In this way, stability of vehicle running could be improved. Secondly, flow fields of the bionic model were computed. Compared with the original model, an obvious vortex was behind the original model, while no vortexes were behind the bionic model. Therefore, convex structures of the bionic model had obvious impacts on flow fields behind the rear view mirror. Airflow separation situations were obvious improved at wheels, windshield and rear side windows of the bionic model. Due to blocking of convex structures of the A pillar and rear view mirror in the bionic model, airflows was hindered and obvious dragging phenomena were formed. Therefore, flow fields in the side window regions could be improved greatly. In addition, the flow field scope under the rear view mirror in the bionic model was also decreased. Ringed vortex structures appeared behind the rear view mirror in the bionic model. The ringed vortex structures were closely interlaced and then extended together backwards. Vortexes behind the rear view mirror in the original model were chaotic, where most of them were attached on the surface of side windows. In the original model, turbulent flows with certain strength were on the right upper corner of the side window region. In the bionic model, no turbulent flows were in the same regions. This result indicated that through using the bionic convex structures, airflows flowing through side windows could be combed and could move backwards towards upper and lower edges of the side windows. It could be predicted that pulsation pressures on the side window surface would surely decrease. Therefore, aerodynamic noises caused by pulsation pressures in side window regions would also be improved correspondingly. Especially in regions behind A pillar-rear view mirrors, the maximum noise reduction amplitude reached about 20 dB.

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Section: Introductionmentioning

confidence: 99%

Numerical simulation on the impact of the bionic structure on aerodynamic noises of sidewindow regions in vehicles

Liu¹,

Li²,

Ding³

2018

J. vibroeng.

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show abstract

“…The paper showed that a match between the measured and computed results is found using several static pressure sensors located at the OSRVM [8]. Moreover, various experimental and simulation studies have been investigated to identify aeroacoustics sources and noise generation of the side mirror [9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic Analysis and Noise-Reducing Design of an Outside Rear View Mirror

2018

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The outside rear view mirror (OSRVM) is installed on the exterior of vehicles to secure the side and rear views of the vehicle, but its extruded design causes unwanted aerodynamic noise and vibration during driving. In this study, additional line holes (inner dents) are made on the inner and outer edges of the mirror housing without a reduction in size in order to enhance the aerodynamic flow and noise around the mirror. Based on computational fluid dynamics (CFD) analysis, this study compares the aerodynamic characteristics of the original and modified mirror models. The comparative analyses verify that the proposed OSRVM model with the inner ducts dramatically improves the velocity profiles and sound pressure levels.

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Direct Aeroacoustic Simulations Based on High Order Discontinuous Galerkin Schemes

Beck¹,

Munz²

2017

CISM International Centre for Mechanical Sciences

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Experimental investigation of an aeroacoustic feedback mechanism on a two-dimensional side mirror model

Cited by 5 publications

References 40 publications

Numerical simulation on the impact of the bionic structure on aerodynamic noises of sidewindow regions in vehicles

Numerical simulation on the impact of the bionic structure on aerodynamic noises of sidewindow regions in vehicles

Aerodynamic Analysis and Noise-Reducing Design of an Outside Rear View Mirror

Direct Aeroacoustic Simulations Based on High Order Discontinuous Galerkin Schemes

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