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The Effect of Tractor-Trailer Flow Interaction on the Drag And Distribution of Drag of Tractor-Trailer Trucks
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English
Abstract
A wind-tunnel study was carried out to determine the influence of some tractor and trailer geometries on the distribution of aerodynamic drag of tractor-trailer trucks. Also investigated were the effects on the drag distribution of drag-reducing devices and of exhaust stacks. The measurements were made on 1/8th-scale models at a Reynolds number of 106.
The shape of the tractor strongly influenced the drag on the trailer. Streamlining the tractor could increase the drag on the trailer to the point that the drag on the tractor-trailer combination increased.
A relatively streamlined conventional tractor was responsible for between 45% and 57% of the total aerodynamic drag at 0° yaw, whereas a relatively unstreamlined cab-over-engine tractor was responsible for between 73% and 82% of the zero-yaw drag.
A streamlined fairing mounted on the tractor increased the drag on the tractor, but decreased the drag on the trailer substantially more than the drag on the tractor increased.
Exhaust stacks were found to significantly reduce the drag on a tractor-trailer combination.
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Authors
Citation
Marks, C. and Buckley, F., "The Effect of Tractor-Trailer Flow Interaction on the Drag And Distribution of Drag of Tractor-Trailer Trucks," SAE Technical Paper 801403, 1980, https://doi.org/10.4271/801403.Also In
References
- Flynn H. Kyropoulos P. “Truck Aerodynamics.” SAE Trans 73 297 308 1963
- Kirsch J.W. Bettes W.H. “Feasibility Study of the S 3 Air Vane and Other Truck Drag Reduction Devices.” Proceedings of the NSF/DOT Conference on the Reduction of the Aerodynamic Drag of Trucks California Institute of Technology Pasadena, Calif. Oct. 1974
- “The DOT/SAE Truck and Bus Fuel Economy Measurements Report.” SAE Report No. P-59 1975
- Buckley F.T. Jr. Sekscienski W.S. “Comparison of Commercially Available Devices for the Reduction of Aerodynamic Drag on Tractor-Trailers.” SAE Trans 84 1743 1753 1975
- Buckley F.T. Jr. Marks C.H. Walston W.H. Jr. “Analysis of Coast-Down Data to Assess Aerodynamic Drag Reduction on Full-Scale Tractor-Trailer Trucks in Windy Environments.” SAE Trans 85 2765 2769 1976
- Marks C.H. Buckley F.T. Jr. Walston W.H. Jr. “An Evaluation of the Aerodynamic Drag Reductions Produced by Various Cab Roof Fairings and a Gap Seal on Tractor-Trailer Trucks.” SAE Trans 85 366 374 1976
- Buckley F.T. Jr. Marks C.H. “A Wind-Tunnel Study of the Effect of Gap Flow and Gap Seals on the Aerodynamic Drag of Tractor-Trailer Trucks,” Journal of Fluids Engineering 100 4 434 438 Dec. 1978