Volume 4, Issue 4, July 2019, Page: 103-117
Experimental Validation for Globally Optimized Tractor-Trailer Base Flaps
Jacob Andrew Freeman, Department of Aeronautics and Astronautics, Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio, USA
Mark Franklin Reeder, Department of Aeronautics and Astronautics, Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio, USA
Anna Christine Demoret, Department of Aeronautics and Astronautics, Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio, USA
Received: Jul. 2, 2019;       Accepted: Jul. 25, 2019;       Published: Aug. 13, 2019
DOI: 10.11648/j.ajtte.20190404.11      View  48      Downloads  17
Using wind-tunnel testing, this study validates a design that was globally optimized under uncertainty and used computational fluid dynamics. The computational study determined a design for a 3-D tractor-trailer base (back-end) drag-reduction device that reduces the wind-averaged drag coefficient by 41% at 57 mph (92 km/h). The wind-tunnel testing applies the same method of including some uncertainties, such that the design is relatively insensitive to variation in wind speed and direction, elevation, and installation accuracy. The validation testing shows a 20.1% reduction in wind-averaged drag coefficient, or 1.3% better than a non-optimized commercial design, and is conducted on a 1/24-scale model of the simplified tractor trailer at a trailer-width-based Reynolds number (ReW) of 4.9x105. Test data include both force and pressure measurements on the simplified tractor trailer, as well as pressure measurements on the tunnel wall. Measurements are taken at static side-slip angles to enable wind-averaged calculations. Since the original computations are conducted for a full-scale tractor-trailer at ReW = 4.4x106, this study does not fully validate the computational design due to the wind tunnel limitations and resulting inability to match the ReW; however, the results show qualitative and quantitative improvement over the non-optimized design.
Experimental Validation in Low-Speed Wind Tunnel, Optimization Under Uncertainty, Uncertainty Quantification, Aerodynamic Shape Optimization, Drag Reduction
To cite this article
Jacob Andrew Freeman, Mark Franklin Reeder, Anna Christine Demoret, Experimental Validation for Globally Optimized Tractor-Trailer Base Flaps, American Journal of Traffic and Transportation Engineering. Vol. 4, No. 4, 2019, pp. 103-117. doi: 10.11648/j.ajtte.20190404.11
Copyright © 2019 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Mason WT Jr, Beebe PS. The drag related flowfield characteristics of trucks and buses. In: Symposium on aerodynamic drag mechanisms of bluff bodies and road vehicles, General Motors Research Laboratories, Plenum Press, 1978.
Cooper KR. Truck aerodynamics reborn – lessons from the past. SAE technical paper 2003-01-3376, 2003. DOI: 10.4271/2003-01-3376.
Leuschen J, Cooper KR. 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. DOI: 10.4271/2006-01-3456.
Freeman JA, Roy CJ. Global optimization under uncertainty and uncertainty quantification applied to tractor-trailer base flaps. ASME J Verification, Validation and Uncertainty Quantification 2016; 1 (2): 021008: 1-16. DOI: 10.1115/1.4033289.
Freeman JA, Roy CJ. Provisional Patent, “A Shape-Optimized Base Flap Geometry for Reducing Aerodynamic Drag of Tractor-Trailers,” 2014, US Provisional Patent No. 61/992,970.
SAE wind tunnel test procedure for trucks and buses. SAE J1252, SAE Recommended Practice, July 1981.
Fuel consumption test procedure – type II. SAE J1321, SAE standard, February 2012.
“Aerodynamics 101,” STEMCO Products Inc., accessed November 14, 2018. http://www.stemco.com/video-gallery /aerodynamics-101 and http://www.stemco.com/product/trailertail
Cooper KR. The effect of front-edge rounding and rear-edge shaping on the aerodynamic drag of bluff vehicles in ground proximity. SAE technical paper 850288, February 1985. DOI: 10.4271/850288.
Storms BL, Ross JC, Heineck JT, Walker SM, Driver DM, Zilliac GG. An experimental study of the ground transportation system (GTS) model in the NASA Ames 7- by 10-ft wind tunnel. NASA/TM-2001-209621, February 2001.
Lanser WR, Ross JC, Kaufman AE. Aerodynamic performance of a drag reduction device on a full-scale tractor/trailer. SAE technical paper 912125, September 1991. DOI: 10.4271/912125.
Visser KD, Grover K, Marin LE. Sealed aft cavity drag reducer. US Patent 8,079,634; 2011, accessed June 27, 2012. http://patft.uspto.gov
Browand F, Radovich C, Boivin M. Fuel savings by means of flow attached to the base of a trailer: field test results. SAE technical paper 2005-01-1016, 2005. DOI: 10.4271/2005-01-1016.
Hsu T-Y, Hammache M, Browand F. Base flaps and oscillatory perturbations to decrease base drag. In: McCallen R, Browand F, Ross J (eds.). Lecture notes in applied and computational mechanics, vol. 19: The aerodynamics of heavy vehicles: trucks, buses, and trains, pp. 303-316. Berlin: Springer; 2004.
Ortega JM, Salari K. An experimental study of drag reduction devices for a trailer underbody and base. 34th fluid dynamics conference, AIAA-2004-2252, 2004.
Barlow JB, Rae WH Jr, Pope A. Low-speed wind tunnel testing, 3d Edition. New York: Jon Wiley & Sons; 1999.
Kline JS, McClintock FA. Describing uncertainties in single-sample experiments. ASME J Mech Eng, 1953, 1: 3-8.
Freeman JA, Roy CJ. Application of optimization under uncertainty: 2-d tractor-trailer base flaps. AIAA-2012-0671, 2012.
Dellinger D. Average wind speed. National Oceanic and Atmospheric Administration, 2008, accessed June 19, 2012. http://lwf.ncdc.noaa.gov/oa/climate/online/ccd/avgwind.html
Gridgen version 15 user manual. Pointwise, Inc., Texas, 2006.
Cobalt version 5.2 user’s manual. Cobalt Solutions, LLC., Ohio, 2011.
Gutierrez WT, Hassan B, Croll RH, Rutledge WH. Aerodynamics overview of the ground transportation systems (GTS) project for heavy vehicle drag reduction. SAE Technical Paper 960906, February 1996. DOI: 10.4271/960906.
“Annual vehicle distance traveled in miles and related data by highway category and vehicle type,” 2016, Table VM-1, Highway Statistics, Office of Highway Patrol Information, Federal Highway Administration, US Department of Transportation, accessed November 14, 2018. https://www.fhwa.dot.gov/policyinformation/ statistics/2016/vm1.cfm.
“US on-highway diesel fuel prices,” 2018, US Energy Information Administration, accessed November 14, 2018. https://www.eia.gov/petroleum/gasdiesel
McCallen R, Couch R, Hsu J, Browand F, Hammache M, Leonard A, Brady M, Salari K, Rutledge W, Ross J, Storms B, Heineck JT, Driver D, Bell J, Zilliac G. Progress in reducing aerodynamic drag for higher efficiency of heavy duty trucks (class 7-8). Office of Scientific and Technical Information, US Department of Energy, December, 1999. DOI: 10.2172/771211.
Browse journals by subject