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Influence of short rear end tapers on the unsteady base pressure of a simplified ground vehicle

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conference contribution
posted on 2016-06-08, 13:59 authored by Giancarlo Pavia, Martin Passmore, Adrian P. Gaylard
Short tapered sections on the trailing edge of the roof, underside and sides of a vehicle are a common feature of the aerodynamic optimization process and are known to have a significant effect on the base pressure and thereby the vehicle drag. In this paper the effects of such high aspect ratio chamfers on the time-dependent base pressure are investigated. Short tapered surfaces, with a chord approximately equal to 4% of the overall model length, were applied to the trailing edges of a simplified passenger car model (the Windsor Body) and base pressure studied via an array of surface pressure tappings. Two sets of configurations were tested. In the first case, a chamfer was applied only to the top or bottom trailing edge. A combination of taper angles was also considered. In the second case, the chamfer was applied to the side edges of the model base, leaving the horizontal trailing edges squared. In all configurations both the base and the slanted surfaces were covered with pressure taps for the entire width to ensure that any asymmetry was captured and two different sampling time were considered (respectively equal to 31.5 s and 630.0 s). The results show the effects produced on the base pressure by the presence of a long period bi-stable behavior, whose characteristics were further investigated by conditional averaging the recorded data and considering the distribution of the rms pressure values recorded over the entire model base.



  • Aeronautical, Automotive, Chemical and Materials Engineering


  • Aeronautical and Automotive Engineering

Published in

SAE World Congress 2016


PAVIA, G., PASSMORE, M.A. and GAYLARD, A.P., 2016. Influence of short rear end tapers on the unsteady base pressure of a simplified ground vehicle. SAE World Congress 2016, Detroit, SAE Technical Paper 2016-01-1590, doi:10.4271/2016-01-1590.


© SAE International


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This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

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This paper was published in SAE Technical Paper 2016-01-1590 and the definitive published version is available at http://dx.doi.org/10.427/2016-01-1590

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SAE Technical Paper;2016-01-1590


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