Pavia_1_FKFSConference.pdf (1.95 MB)
Characterisation of wake bi-stability for a square-back geometry with rotating wheels
chapter
posted on 2018-10-26, 13:13 authored by Giancarlo Pavia, Martin PassmoreIn this paper the effects produced by the wheels on the bi-stable reflectional symmetry breaking (RSB) mode seen for the wake of a square-back geometry (Grandemange et al. [11]) are investigated considering a modified version of the Windsor body already studied in Perry et al. [18]. The contribution of the wheels and their rotation to the changes in the base pressure distribution and the wake topology is characterised by means of pressure tappings and 2D-3C particle image velocimetry. Balance measurements are used to further characterise the changes in the strength of the RSB mode. For the pure square-back configuration, the results show a general increase of the base drag as a consequence of the strengthening of the suction over the lower portion of base, due to the formation of a pair of counter rotating vortices acting close to the bottom trailing edge. At the same time, the RSB mode is weakened, leading to a reduction in the fluctuations recorded for the lateral component of the aerodynamic force. The sensitivity of the RSB mode to small changes in the shape of the model’s trailing edges is characterised by looking at the effects produced by short tapers, with a slant angle of 12° and a chord equal to 4% of the model length, applied to either the horizontal or the vertical trailing edges. The results show that the RSB mode disappears when the effect of the wheels is paired to the upwash generated by the slanted surface (when applied to the bottom trailing edge), although it is still clearly visible when the tapers are applied to the side edges of the base, in contrast with the results reported by Pavia et al. [16] for the same geometry without wheels.
Funding
The authors would like to thank Jaguar Land Rover for the financial support
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Aeronautical and Automotive Engineering
Published in
Progress in Vehicle Aerodynamics and Thermal ManagementPages
93 - 109Citation
PAVIA, G. and PASSMORE, M.A., 2017. Characterisation of Wake Bi-stability for a Square-Back Geometry with Rotating Wheels. IN: Wiedemann J. (eds) Progress in Vehicle Aerodynamics and Thermal Management (FKFS 2017). Chaim: Springer, pp. 93-109.Publisher
SpringerVersion
- AM (Accepted Manuscript)
Publisher statement
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/Publication date
2017Notes
This paper was presented at the 11th FKFS Conference, Stuttgart, September 26-27, 2017. This is a pre-copyedited version of a contribution published in Wiedemann J. (eds) Progress in Vehicle Aerodynamics and Thermal Management (FKFS 2017) published by Springer. The definitive authenticated version is available online via https://doi.org/10.1007/978-3-319-67822-1_6.ISBN
9783319678214;9783319678221Publisher version
Language
- en