Scaling Laws in Automotive Aeroacoustics

Wickern, Gerhard; Brennberger, Martin

doi:10.4271/2009-01-0180

Cited by 8 publications

(3 citation statements)

References 7 publications

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“…Therefore, the known scaling laws for monopole (W∼U 4 ), dipole (W∼U 6 ) and quadrupole (W∼U 8 ) may give an over estimation or an under estimation if these laws were applied. 66…”

Section: Resultsmentioning

confidence: 99%

Neural networks assisted computational aero-acoustic analysis of an isolated tire

Uddin

Niazi

Arafat

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part D:

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The computational aero-acoustic study of an isolated passenger car tire is carried out to understand the effect of dimensions of longitudinal tire grooves and operational parameters (velocity and temperature) on tire noise. The computational fluid dynamics and acoustic models are used to obtain aero-acoustic tire noise at near-field and far-field receivers around the tire and artificial neural networks-based regression are used to study the highly non-linear and interactive causal relationships in the system. Unsteady Reynolds-Averaged Navier-Stokes based realizable k-epsilon model is used to solve the flow field in the computational domain. The Ffowcs Williams and Hawkings model is used to obtain aero-acoustic tire noise at far-field positions. Spectral analysis is used to convert the output time domain to frequency domain and to obtain A-weighted sound pressure level. Artificial neural network–based response surface regression is conducted to understand casual relationships between A-weighted sound pressure level and control variables (Groove depth, Groove width, Temperature and velocity). Maximum A-weighted sound pressure level is observed in the wake region of the tire model. The interaction study indicates that ∼10% reduction in the aero-acoustic emissions is possible by selecting appropriate combinations of groove width and groove depth. The interaction of velocity with width is found to be most significant with respect to A-weighted sound pressure level at all receivers surrounding the tire. The interaction of operational parameters, that is, velocity and temperature are found to be significant with respect to A-weighted sound pressure level at wake and front receivers. Therefore, the regional speed limits and seasonal temperatures need to be considered while designing the tire to achieve minimum aero-acoustic emissions.

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“…Therefore, the known scaling laws for monopole (W∼U 4 ), dipole (W∼U 6 ) and quadrupole (W∼U 8 ) may give an over estimation or an under estimation if these laws were applied. 66…”

Section: Resultsmentioning

confidence: 99%

Neural networks assisted computational aero-acoustic analysis of an isolated tire

Uddin

Niazi

Arafat

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…By assessing the sensitivity of various exterior and interior noise sources to flow speed, a valuable insight can be gained into the physics of the sound sources. 28 Whilst the overall broadband noise of a vehicle typically scales with u 6 , in smaller details these scaling laws can vary and can combine to form a sensitivity made up of a combination of different powers. Therefore, since wind noise is particularly sensitive to wind speed, care must be taken to either keep wind speed constant during wind tunnel tests or recorded when testing onroad.…”

Section: Fundamental Aeroacoustic Sourcesmentioning

confidence: 99%

Automotive aeroacoustics: An overview

Oettle

Sims-Williams

2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractVehicle aeroacoustic performance has a strong influence on customer perception and also has importance for safety and comfort. Wind noise performance was once differentiated by the quality of sealing. Today, achieving competitive wind noise performance also depends on minimising aeroacoustic noise sources generated by the vehicle form, and on attenuation in the noise pathway from sources on the exterior to the vehicle interior. Attenuation in the noise pathway from sources on the exterior to the vehicle interior, especially through glazed surfaces, will continue to play an important role in controlling cabin noise, with a particular emphasis on achieving attenuation efficiently in terms of component mass. The human brain is not only sensitive towards the level of steady broadband noise, but distinctive features such as tonality or modulation draw the attention of the vehicle occupant and impact negatively on perception. Complex indices are often required to define good wind noise performance. This includes the consideration of multiple frequency bands and effects of the range of yaw angles experienced on-road. A key to achieving future vehicle refinement is bringing together an understanding of unsteady onset flow conditions, their impact on cabin sound pressure level and modulation and in turn the impact of noise level and modulation on psychoacoustic perception.

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“…These usually occur at mid and high frequencies and, as dipole sources, they approximately scale with velocity to the power of 6 (e.g. : as discussed by [22]). Tonal noise sources (roof racks, antenna, etc.)…”

Section: Introductionmentioning

confidence: 99%

The Effects of Unsteady Flow Conditions on Vehicle in Cabin and External Noise Generation

Kounenis¹,

Sims-Williams²,

Dominy³

et al. 2015

SAE Technical Paper Series

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Citation for published item:uounenisD ghrlmpos nd imsEillimsD hvid nd hominyD oert nd fersonD ergnth¤ el nd yettleD xihols nd preemnD glire @PHISA 9he e'ets of unstedy )ow onditions on vehile in in nd externl noise genertionF9D ei tehnil pper seriesF F PHISEHIEISSSF Further information on publisher's website: httpsXGGdoiForgGIHFRPUIGPHISEHIEISSS Publisher's copyright statement:Copyright c 2015 SAE International. This paper is posted on this site with permission from SAE International. It may not be shared, downloaded, duplicated, printed or transmitted in any manner, or stored on any additional repositories or retrieval system without prior written permission from SAE. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractA vehicle driving on the road experiences unsteady flow conditions which are not generally reproduced in the development environment. This paper investigates the potential importance of this difference to aeroacoustics and hence to occupant perception and proposes a methodology to enable better ranking of designs by taking account of wind noise modulation.Two approaches of reproducing the effects of unsteady wind on aeroacoustics were investigated: an active wind tunnel Turbulence Generation System (TGS) and a quasi-steady approach based on measurements at a series of fixed yaw angles. A number of tools were used to investigate the onset flow and its impacts, including roofmounted probe, acoustic heads and surface microphones. External noise measurements help to reveal the response of separate exterior noise sources to yaw.The noise experienced by the driver or passenger ear facing the side-glass is dominated by increased sound pressure levels when the adjacent side-glass is the leeward side of the vehicle with some non-linear effects as leeward yaw produces first accelerated flow and then separation.In part because of non-linearity in response to yaw, a challenging parameter for a wind tunnel simulation of dynamic yaw is achieving a wide enough variation in yaw angle and this work suggests that considering an appropriate range of yaw angles is more important than capturing the dynamics.In terms of passenger perception, the most important effect of a time-varying onset flow was demonstrated to be the modulation of wind noise rather than the increase in time-averaged cabin noise. For the case considered, at 130 km/h, the impact of wind-noise modulation was found to be equivalent to an extra 1-2 dBA in terms of passenger perception, while the increment in time-averaged cabin noise w...

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Scaling Laws in Automotive Aeroacoustics

Cited by 8 publications

References 7 publications

Neural networks assisted computational aero-acoustic analysis of an isolated tire

Neural networks assisted computational aero-acoustic analysis of an isolated tire

Automotive aeroacoustics: An overview

The Effects of Unsteady Flow Conditions on Vehicle in Cabin and External Noise Generation

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