repository 2013-01-0463.pdf (2.52 MB)
Download file

The impact of underbody roughness on rear wake structure of a squareback vehicle

Download (2.52 MB)
conference contribution
posted on 30.09.2016, 12:35 by Anna Perry, Martin Passmore
In this paper the effects of a rough underbody on the rear wake structure of a simplified squareback model (the Windsor model) is investigated using balance measurements, base pressure measurements and two and three component planar PIV. The work forms part of a larger study to develop understanding of the mechanisms that influence overall base pressure and hence the resulting aerodynamic drag. In the work reported in this paper the impact of a rough underbody on the base pressure and wake flow structures is quantified at three different ground clearances. The underbody roughness has been created through the addition of five roughness strips to the underbody of the model and the effects on the wake at ground clearances of 10.3%, 17.3% and 24.2% of the model height are assessed. All work has been carried out in the Loughborough University Large Wind Tunnel with a scale model giving a blockage ratio of 4.4% for a smooth under-body or 4.5% with the maximum thickness roughness strips. The tests are conducted with a fixed ground plane. Results are presented for the base pressure distribution and these are compared against the stream-wise PIV results. This work demonstrates the need for rough underbody structures to be considered during base pressure investigations before any model scale work is conducted due to their influence on the wake structures. Copyright © 2013 SAE International.



  • Aeronautical, Automotive, Chemical and Materials Engineering


  • Aeronautical and Automotive Engineering

Published in

SAE Technical Papers




PERRY, A.K. and PASSMORE, M., 2013. The impact of underbody roughness on rear wake structure of a squareback vehicle. SAE Technical Paper 2013-01-0463, doi:10.4271/2013-01-0463.


© SAE International


AM (Accepted Manuscript)

Publication date



This paper was presented at the SAE 2013 World Congress & Exhibition. Copyright © 2013 SAE International. This paper is posted on this site with permission from SAE International, and is for viewing only. Further use or distribution of this paper is not permitted without permission from SAE.



Book series

SAE Technical Paper;2013-01-0463



Usage metrics