This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Aerodynamic Effects of Roof Deflector and Cab Side Extenders for Truck-Trailer Combinations
Technical Paper
2011-01-2284
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Today there are a large variety of drag-reducing devices for
heavy trucks that are commonly used, for example, roof deflectors,
cab side extenders and chassis fairings. These devices are often
proven to be efficient, reducing the total aerodynamic resistance
for the vehicle. However, the drag-reducing devices are usually
identical for a specific pulling vehicle, independent of the layout
of the vehicle combination.
In this study, three vehicle combinations were analyzed. The
total length of the vehicles varied between 10.10 m and 25.25 m.
The combinations consisted of a rigid truck in combination with one
or two cargo units. The size of the gap between the cargo units
differed between the vehicle combinations. There were also three
configurations of each vehicle combination with different
combinations of roof deflector and cab side extenders, yielding a
total number of nine configurations.
The aim of this investigation was to determine the aerodynamic
effects of the roof deflector and cab side extenders as a function
of the type of vehicle combination. Important factors were the
total length of the vehicle combination and the influence of the
drag reducing devices further downstream. The investigation was
performed using Computational Fluid Dynamics (CFD).
The results from the investigation showed that the effect of the
two drag-reducing devices analyzed was different depending on the
type of vehicle combination. It was established that the roof
deflector and cab side extenders were always efficient in reducing
drag both in 0° yaw and 5° yaw but the magnitudes differed between
the configurations. The largest effects of the drag-reducing
devices were seen for the truck including the 1st cargo unit; the
influence of the drag-reducing devices on the 2nd cargo unit was
smaller. The aerodynamic reductions were diminishing downstream,
why it was concluded that it is of great importance to improve the
aerodynamic design of the rest of the vehicle to maintain the
positive effects of the drag reducing devices.
Recommended Content
Authors
Topic
Citation
Martini, H., Bergqvist, B., Hjelm, L., and Löfdahl, L., "Aerodynamic Effects of Roof Deflector and Cab Side Extenders for Truck-Trailer Combinations," SAE Technical Paper 2011-01-2284, 2011, https://doi.org/10.4271/2011-01-2284.Also In
References
- Gullberg, P. “Optimization of the Flow Process in Engine Bays - 3D Fan Modelling Strategies,” Licentiate thesis Chalmers University of Technology Gothenburg 2009
- Lögdberg, O. “Turbulent Boundary Layer Separation and Control,” Ph.D. thesis KTH Stockholm 2008
- Hucho, W.H. “Aerodynamik des Automobils, 5 Auflage” Viweg + Teubner/GWV Fachverlage GmbH Wiesbaden 978- 3-528-03959-2 2008
- Leuschen, J. Cooper, K. “Full-Scale Wind Tunnel Tests of Production and Prototype, Second-Generation Aerodynamic Drag-Reducing Devices for Tractor-Trailers,” SAE Technical Paper 2006-01-3456 2006 10.4271/2006-01-3456
- Marks, C. Buckley, F. Walston, W. “An Evaluation of the Aerodynamic Drag Reductions Produced by Various Cab Roof Fairings and a Gap Seal on Tractor-Trailer Trucks,” SAE Technical Paper 760105 1976 10.4271/760105
- Kim, C. H. Youn, C. B. “Aerodynamic Effect of Roof-Fairing System on a Heavy-Duty Truck,” International Journal of Automotive Technology 6 3 221 227 2005
- Dominy, R. G. “Fuel Saving by the Optimized Use of Cab Roof Fairings for Typical Articulated Vehicle Operating Cycles,” Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 211 3 219 226 1997
- Castellucci, P. Salari, K. “Computational Simulation of Tractor-Trailer Gap Flow with Drag-Reducing Aerodynamic Devices,” SAE Technical Paper 2005-01-3625 2005 10.4271/2005-01-3625
- Martini, H. Bergqvist, B. Hjelm, L. Löfdahl, L. “Influence of Different Truck and Trailer Combinations on the Aerodynamic Drag,” SAE Technical Paper 2011-01-0179 2011 10.4271/2011-01-0179
- Gilhaus, A. Hau, E. Künstner, R. Potthoff, J. “Über den Luftwiderstand von Fernlastzügen, Ergebnisse aus Modellmessungen im Windkanal - Teil I,” Automobil-Industrie 3/79 1979
- Gilhaus, A. Hau, E. Künstner, R. Potthoff, J. “Über den Luftwiderstand von Fernlastzügen, Ergebnisse aus Modellmessungen im Windkanal - Teil II,” Automobil-Industrie 3/80 1980
- “STAR-CCM+ Manual”
- Greenbaum, J. Kluger, M. “Aerodynamic and Mechanical Drag Characteristics of Light Trucks and Truck-Trailer Combinations,” SAE Technical Paper 932976 1993 10.4271/932976