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Investigations of Sunroof Buffeting in an idealised Generic Vehicle Model - Part I: Experimental Results

Islam, M. and Decker, F. and Hartmann, M. and Jäger, A. and Lemke, T. and Ocker, J. and Schwarz, V. and Ullrich, F. and Schröder, Andreas and Heider, André (2007) Investigations of Sunroof Buffeting in an idealised Generic Vehicle Model - Part I: Experimental Results. 14th AIAA/CEAS Aeroacoustics Conference / (29th AIAA Aeroacoustics Conference), 2008-05-05 - 2008-05-07, Vancouver (Canada).

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Official URL: http://www.aiaa.org

Abstract

This paper is the first of a two-paper series that describes the experimental portion of a long-term, ongoing investigation - carried out by a consortium of the German automotive manufacturers Audi, BMW, Daimler, Porsche and Volkswagen - of the feasibility of predicting buffeting phenomena by means of computational fluid dynamics (CFD). The numerical simulations carried out as part of the study are reported on in the second paper of the series. Sunroof and side-window buffeting is a common phenomenon in passenger cars, and can cause considerable discomfort to the passengers due to the high sound-pressure levels (SPL) that are generated. The general physical mechanism, whereby an unsteady shear layer in the sunroof or window opening induces an acoustic resonance in the passenger compartment, is well-understood. However, experience has shown that making a priori predictions about the tendency of a given configuration to experience buffeting - essential in the early stages of the vehicle design process - with the required degree of reliability and accuracy is not possible. In the vehicle development process, pragmatic design solutions for suppressing buffeting at various wind speeds and geometric configurations are found experimentally. Previous work carried out by members of the consortium has shown that clearly identifying and isolating the individual factors that influence buffeting in real vehicles is very diffcult. They range from the geometry of the sunroof or side window, including small geometric details of the surrounding vehicle parts, to the quality of the oncoming flow, to the arrangement of the internal volume of the vehicle. Moreover, it has been found that the interaction of the fluid flow with the vehicle structure has a particularly large influence on buffeting behaviour and makes the analysis of the individual physical phenomena that contribute to the overall effect very diffcult. In order carry out a systematic analysis of these issues, the consortium devised a long-term project in which the first step, presented in this two-part publication, isolates and investigates only the issues related to fluid dynamics and acoustics, and ensures that the other aforementioned factors influencing buffeting play no role. Rigorous studies of this type which are also directly relevant to vehicle design are not found in the present literature. Only sunroof buffeting was considered in the present study, as the physical mechanism is essentially identical to that of side-window buffeting.

Document Type:Conference or Workshop Item (Speech, Paper)
Title:Investigations of Sunroof Buffeting in an idealised Generic Vehicle Model - Part I: Experimental Results
Authors:
AuthorsInstitution or Email of Authors
Islam, M.Audi AG, Wind-Tunnel Centre, 85045 Ingolstadt, Germany
Decker, F.Volkswagen AG, Letterbox 1697, 38436 Wolfsburg, Germany
Hartmann, M.Volkswagen AG, Letterbox 1777, 38436 Wolfsburg, Germany
Jäger, A.Daimler AG, HPC X715, 71059 Sindelfingen, Germany
Lemke, T.Porsche AG, Dept. EIA3, 71287 Weissach, Germany
Ocker, J.Porsche AG, Dept. EGA3, 71287 Weissach, Germany
Schwarz, V.Daimler AG, HPC X715, 71059 Sindelfingen, Germany
Ullrich, F.BMW AG, Dept. EG-42, 80788 Munich, Germany
Schröder, AndreasUNSPECIFIED
Heider, AndréUNSPECIFIED
Date:2007
Refereed publication:No
In SCOPUS:No
In ISI Web of Science:No
Volume:Session 15-AA-15
Page Range:pp. 1-22
Series Name:DVD-ROM Conference Proceedings
Status:Published
Keywords:fluid dynamics and acoustics, Investigations of Sunroof Buffeting, computational fluid dynamics (CFD)
Event Title:14th AIAA/CEAS Aeroacoustics Conference / (29th AIAA Aeroacoustics Conference)
Event Location:Vancouver (Canada)
Event Type:international Conference
Event Dates:2008-05-05 - 2008-05-07
Organizer:AIAA
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Flight Physics
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Experimental Methods
Deposited By: Ilka Micknaus
Deposited On:13 Nov 2007
Last Modified:15 Jan 2010 01:52

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