passmore3.pdf (1.09 MB)
Experimental study of multiple-channel automotive underbody diffusers
journal contribution
posted on 2010-07-20, 13:25 authored by Lydia Jowsey, Martin PassmoreUnderbody diffusers are used widely in race car applications because they can
significantly improve the cornering capacity of the vehicle through the generation of a
downforce. They are also likely to have a wider role in reducing the drag in road vehicles as it
becomes increasingly important to reduce emissions of carbon dioxide.
This paper reports on a wind tunnel investigation, using a simplified bluff body model, into
the effect of splitting a simple plane diffuser into multiple channels. Tests are reported for a
range of diffuser geometries suitable for road and race car applications. The results for the lift,
the drag, and the incremental changes to the lift-to-drag ratio are reported and discussed in
terms of the underbody pressures.
While broadly similar trends to the single-channel plane diffuser are seen in the multiplechannel
diffuser configurations, it was found that the effect of increasing the number of channels
depended on the flow regimes present in the plane diffuser. At angles just above the plane diffuser
optimum, where the flow is partially separated, the multiple-channel configurations give large
improvements in the downforce with minimal increase in the drag, significantly extending the
performance envelope. The pressure maps indicate that the gains occur through improved
diffuser pumping and pressure recovery in both the inner and the outer channels.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Aeronautical and Automotive Engineering
Citation
JOWSEY, L. and PASSMORE, M.A., 2010. Experimental study of multiple-channel automotive underbody diffusers. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 224(7), pp. 865-879Publisher
Professional Engineering Publishing / © IMECHEVersion
- VoR (Version of Record)
Publication date
2010Notes
This article has been published in the journal, Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering [© IMechE]. The definitive version is available at: http://dx.doi.org/10.1243/09544070JAUTO1339ISSN
0954-4070;2041-2991Language
- en