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Computational investigation into the sensitivity of a simplified vehicle wake to small base geometry changes

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journal contribution
posted on 08.01.2019, 13:24 by Sophie Luckhurst, Max Varney, Hao XiaHao Xia, Martin Passmore, Adrian P. Gaylard
For vehicles with a squareback geometry, for example Sports Utility Vehicles (SUVs), base pressure drag is a large contributor to overall drag. Simple passive techniques, such as tapering, can reduce drag significantly but at a large aesthetic and functional cost. Therefore, very small base geometry changes have been investigated. An experimentally validated methodology has used Detached Eddy Simulations (DES) to obtain time-averaged and instantaneous data; allowing the effect of horizontal base slats on global forces and wake structures to be presented. The small geometry modifications have caused substantial changes to the base pressure distribution with the main mechanisms of change being identified and observed close to the model surfaces. A region of separation is seen below each slat corresponding to reduced pressure whilst high pressure regions attributed to stagnation are increased. The combined effect is a statistically significant drag reduction of 4 counts (1 count = 0.001 CD) when a slat is added at 3/4 of the base height. The results show the scope for very small changes to a simplified road vehicle, in areas that have not previously been explored, to reduce overall drag with minimal aesthetic penalties. This understanding provides the impetus for new approaches in real vehicle development.

Funding

This project is partially funded by Jaguar Land Rover.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Aeronautical and Automotive Engineering

Published in

Journal of Wind Engineering and Industrial Aerodynamics

Volume

185

Pages

1-15

Citation

LUCKHURST, S. ... et al, 2018. Computational investigation into the sensitivity of a simplified vehicle wake to small base geometry changes. Journal of Wind Engineering and Industrial Aerodynamics, 185, pp.1-15.

Publisher

© Elsevier

Version

AM (Accepted Manuscript)

Publisher statement

This paper was accepted for publication in the journal Journal of Wind Engineering and Industrial Aerodynamics and the definitive published version is available at https://doi.org/10.1016/j.jweia.2018.12.010

Acceptance date

10/12/2018

Publication date

2018-12-27

Copyright date

2019

ISSN

0167-6105

Language

en