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Some Salient Features Of The Time-Averaged Ground Vehicle Wake
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English
Abstract
For a basic ground vehicle type of bluff body, the time averaged wake structure is analysed. At a model length based Reynolds number of 4.29 million, detailed pressure measurements, wake survey and force measurements were done in a wind tunnel. Some flow visualisation results were also obtained. Geometric parameter varied was base slant angle. A drag breakdown revealed that almost 85 % of body drag is pressure drag. Most of this drag is generated at the rear end.
Wake flow exhibits a triple deck system of horseshoe vortices. Strength, existence and merging of these vortices depend upon the base slant angle.
Characteristic features of the wake flow for the low drag and high drag configurations is described. Relevance of these phenomena to real ground vehicle flow is addressed.
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Ahmed, S., 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.Also In
Automobile Aerodynamics; Wakes, Wind Effect, Vehicle Development
Number: SP-0569; Published: 1984-03-01
Number: SP-0569; Published: 1984-03-01
References
- Morel: T. The Effect of Base Slant on the Flow Pattern and Drag of three-dimensional Bodies with Blunt Ends Symposium on Aerodynamic Drag Mechanisms of Bluff Bodies and Road Vehicles Sovran G. et al. Plenum Press New York 1978 191 226
- Trienes H. Der Normalwindkanal der Deutschen Forschungsanstalt fur Luft- und Raumfahrt (DFL) in Braunschweig Zeitschrift fur Flugwissenschaften 12 1964 4 135 142
- Riegels F.W. Wuest W. Der 3-m Windkanal der Aerodynamischen Versuchsanstalt Göttingen Zeitschrift für Flugwissenschaften 9 1961 222 228
- Ahmed S.R. Baumert W. The Structure of Wake Flow Behind Road Vehicles Symposium on Aerodynamics of Transportation Morel T. et al. ASME New York 1979 93 103
- Ahmed: S.R. Wake Structure of Typical Automobile Shapes ASME Journal of Fluids Engineering 103 1981 162 169
- Ahmed: S.R. Influence of Base Slant on Wake Structure and Drag of Road Vehicles ASME Journal of Fluids Engineering 105 1983 429 434
- Hucho: W.-H. The Aerodynamic Drag of Cars. Current Understanding, Unresolyed Problems and Future Prospects Symposium Proceedings 7 40