This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Parametric Study of Reduced Span Side Tapering on a Simplified Model with Wheels
Technical Paper
2020-01-0680
ISSN: 0148-7191,
e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Many modern vehicles have blunt rear end geometries for design aesthetics and practicality; however, such vehicles are potentially high drag. The application of tapering; typically applied to an entire edge of the base of the geometry is widely reported as a means of reducing drag, but in many cases, this is not practical on real vehicles. In this study side tapers are applied to only part of the side edge of a simplified automotive geometry, to show the effects of practical implementations of tapers.
The paper reports on a parametric study undertaken in Loughborough University’s Large Wind Tunnel with the ¼ scale Windsor model equipped with wheels. The aerodynamic effect of implementing partial side edge tapers is assessed from a full height taper to a 25% taper in both an upper and lower body configuration. These were investigated using force and moment coefficients, pressure measurements and planar particle image velocimetry (PIV). These geometries showed that the drag reductions are maximised with a 50% span, generating a vertically symmetric wake and less taper drag contribution when compared to a full span taper.
Authors
Citation
Varney, M., Passmore, M., Swakeen, R., and Gaylard, A., "Parametric Study of Reduced Span Side Tapering on a Simplified Model with Wheels," SAE Technical Paper 2020-01-0680, 2020.Also In
References
- JATO , “Demand for SUVs Slows to Lowest Recorded Rate in June, Indicating that Registrations May Have Peaked in the European Market,” https://www.jato.com/demand-for-suvs-slows-to-lowest-recorded-rate-in-june-indicating-that-registrations-may-have-peaked-in-the-european-market/, 2019.
- Brown, Y.A.I., Windsor, S., and Gaylard, A.P. , “The Effect of Base Bleed and Rear Cavities on the Drag of an SUV,” SAE Technical Paper 2010-01-0512, 2010, https://doi.org/10.4271/2010-01-0512.
- Depardon, S., Lasserre, J., Brizzi, L.E., and Borée, J. , “¼ Scale Vehicle Wake Pattern Analysis Using Near-Wall PIV,” SAE World Congr. 2006(724), 2006.
- Pavia, G., Passmore, M., and Gaylard, A. , “Influence of Short Rear End Tapers on the Unsteady Base Pressure of a Simplified Ground Vehicle,” SAE Technical Paper 2016-01-1590, 2016, https://doi.org/10.4271/2016-01-1590.
- Perry, A.-K., Passmore, M., and Finney, A. , “Influence of Short Rear End Tapers on the Base Pressure of a Simplified Vehicle,” SAE Int. J. Passeng. Cars - Mech. Syst. 8:317-327, 2015, doi:10.4271/2015-01-1560.
- Varney, M., Passmore, M., and Gaylard, A. , “The Effect of Passive Base Ventilation on the Aerodynamic Drag of a Generic SUV Vehicle,” SAE Int. J. Passeng. Cars - Mech. Syst. 10:345-357, 2017, doi:10.4271/2017-01-1548.
- Howell, J. and Le Good, G. , “The Effect of Backlight Aspect Ratio on Vortex and Base Drag for a Simple Car-Like Shape,” SAE Technical Paper 2008-01-0737, 2008, https://doi.org/10.4271/2008-01-0737.
- Grandemange, M., Mary, A., Gohlke, M., and Cadot, O. , “Effect on Drag of the Flow Orientation at the Base Separation of a Simplified Blunt Road Vehicle,” Exp. Fluids 54(5), 2013, doi:10.1007/s00348-013-1529-z.
- Ahmed, S.R., Ramm, G., and Faltin, G. , “Some Salient Features of the Time-Averaged Ground Vehicle Wake,” SAE Technical Paper 840300, 1984, https://doi.org/10.4271/840300.
- Littlewood, R. and Passmore, M. , “The Optimization of Roof Trailing Edge Geometry of a Simple Square-Back,” SAE Technical Paper 2010-01-0510, 2010, https://doi.org/10.4271/2010-01-0510.
- Evrard, A., Cadot, O., Herbert, V., Ricot, D. et al. , “Fluid Force and Symmetry Breaking Modes of a 3D Bluff Body with a Base Cavity,” J. Fluids Struct. 61:99-114, 2016, doi:10.1016/j.jfluidstructs.2015.12.001.
- Howell, J., Sims-Williams, D., Sprot, A., Hamlin, F., and Dominy, R. , “Bluff Body Drag Reduction with Ventilated Base Cavities,” SAE Int. J. Passeng. Cars - Mech. Syst. 2012-01-0171 5:152-160, 2012, doi:10.4271/2012-01-0171.
- Duell, E.G. and George, A.R. , “Experimental Study of a Ground Vehicle Body Unsteady near Wake,” SAE Technical Paper 1999-01-0812, 1999, https://doi.org/10.4271/1999-01-0812.
- Modi, V.J. , “Moving Surface Boundary-Layer Control : A Review,” J. Fluids Struct. 11:627-663, 1997, doi:10.1006/jfls.1997.0098.
- Seifert, A., Shtendel, T., and Dolgopyat, D. , “From Lab to Full Scale Active Flow Control Drag Reduction: How to Bridge the Gap?” J. Wind Eng. Ind. Aerodyn. 147:262-272, 2015, doi:https://doi.org/10.1016/j.jweia.2015.09.012.
- Howell, J., Passmore, M., and Tuplin, S. , “Aerodynamic Drag Reduction on a Simple Car-like Shape with Rear Upper Body Taper,” SAE Int. J. Passeng. Cars - Mech. Syst. 6:52-60, 2013, doi:10.4271/2013-01-0462.
- Varney, M., Passmore, M., and Gaylard, A. , “Parametric Study of Asymmetric Side Tapering in Constant Cross Wind Conditions,” WCX World Congr. Exp. 11(3):213-223, 2018, doi:https://doi.org/10.4271/2018-01-0718.
- Pavia, G., Passmore, M., and Varney, M. , “Low-Frequency Wake Dynamics for a Square-Back Vehicle with Side Trailing Edge Tapers,” J. Wind Eng. Ind. Aerodyn. 184(December 2018):417-435, 2019.
- Li, R., Borée, J., Noack, B.R., Cordier, L., and Harambat, F. , “Drag Reduction of a Yawed Car Model by Combining Fluidic Flaps and Turbulence Control,” ISBN 9788894364200, Presentation Only, 2018.
- de la Cruz, G., Brackston, J.M. , R.D., and Morrison, J.F., “Adaptive Base-Flaps under Variable Cross-Wind,” SAE Tech. Pap. Ser. 1, 2017, doi:10.4271/2017-01-7000.
- Johl, G. , “The Design and Performance of a 1.9mx1.3m Indraft Wind Tunnel,” PhD thesis, Aeronautical and Automotive Engineering, Loughborough University, 2010.
- SAE Standard J1594 , “SAE International Vehicle Aerodynamics Terminology,” Rev Dec. 1994.
- Carr, G.W. and Stapleford, W.R. , “Blockage Effects in Automotive Wind-Tunnel Testing,” SAE International Congress and Exposition, 1986, doi:10.4271/860093.
- Coleman, H.W. and Steele, W.G. , Experimentation, Validation, and Uncertainty Analysis for Engineers (John Wiley & Sons, 2009).
- Wood, D. , “The Effect of Rear Geometry Changes on the Notchback Flow Field,” Loughborough University, 2015.
- Pavia, G., Passmore, M., and Sardu, C. , “Evolution of the Bi-Stable Wake of a Square-Back Automotive Shape,” Exp. Fluids 59(1):1-20, 2018, doi:10.1007/s00348-017-2473-0.
- Adrian, L., Adrian, R.J., and Westerweel, J. , Particle Image Velocimetry (Cambridge University Press, 2011). ISBN:9780521440080.
- Hollis, D. , “Particle Image Velocimetry in Gas Turbine Combustor Flow Fields,” Loughborough University, 2004.