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Experimental Validation for Globally Optimized Tractor-Trailer Base Flaps

Received: 2 July 2019     Accepted: 25 July 2019     Published: 13 August 2019
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Abstract

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.

Published in American Journal of Traffic and Transportation Engineering (Volume 4, Issue 4)
DOI 10.11648/j.ajtte.20190404.11
Page(s) 103-117
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2019. Published by Science Publishing Group

Keywords

Experimental Validation in Low-Speed Wind Tunnel, Optimization Under Uncertainty, Uncertainty Quantification, Aerodynamic Shape Optimization, Drag Reduction

References
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[2] Cooper KR. Truck aerodynamics reborn – lessons from the past. SAE technical paper 2003-01-3376, 2003. DOI: 10.4271/2003-01-3376.
[3] 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.
[4] 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.
[5] 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.
[6] SAE wind tunnel test procedure for trucks and buses. SAE J1252, SAE Recommended Practice, July 1981.
[7] Fuel consumption test procedure – type II. SAE J1321, SAE standard, February 2012.
[8] “Aerodynamics 101,” STEMCO Products Inc., accessed November 14, 2018. http://www.stemco.com/video-gallery /aerodynamics-101 and http://www.stemco.com/product/trailertail
[9] 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.
[10] 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.
[11] 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.
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[14] 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.
[15] 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.
[16] Barlow JB, Rae WH Jr, Pope A. Low-speed wind tunnel testing, 3d Edition. New York: Jon Wiley & Sons; 1999.
[17] Kline JS, McClintock FA. Describing uncertainties in single-sample experiments. ASME J Mech Eng, 1953, 1: 3-8.
[18] Freeman JA, Roy CJ. Application of optimization under uncertainty: 2-d tractor-trailer base flaps. AIAA-2012-0671, 2012.
[19] 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
[20] Gridgen version 15 user manual. Pointwise, Inc., Texas, 2006.
[21] Cobalt version 5.2 user’s manual. Cobalt Solutions, LLC., Ohio, 2011.
[22] 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.
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Cite This Article
  • APA Style

    Jacob Andrew Freeman, Mark Franklin Reeder, Anna Christine Demoret. (2019). Experimental Validation for Globally Optimized Tractor-Trailer Base Flaps. American Journal of Traffic and Transportation Engineering, 4(4), 103-117. https://doi.org/10.11648/j.ajtte.20190404.11

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    ACS Style

    Jacob Andrew Freeman; Mark Franklin Reeder; Anna Christine Demoret. Experimental Validation for Globally Optimized Tractor-Trailer Base Flaps. Am. J. Traffic Transp. Eng. 2019, 4(4), 103-117. doi: 10.11648/j.ajtte.20190404.11

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    AMA Style

    Jacob Andrew Freeman, Mark Franklin Reeder, Anna Christine Demoret. Experimental Validation for Globally Optimized Tractor-Trailer Base Flaps. Am J Traffic Transp Eng. 2019;4(4):103-117. doi: 10.11648/j.ajtte.20190404.11

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  • @article{10.11648/j.ajtte.20190404.11,
      author = {Jacob Andrew Freeman and Mark Franklin Reeder and Anna Christine Demoret},
      title = {Experimental Validation for Globally Optimized  Tractor-Trailer Base Flaps},
      journal = {American Journal of Traffic and Transportation Engineering},
      volume = {4},
      number = {4},
      pages = {103-117},
      doi = {10.11648/j.ajtte.20190404.11},
      url = {https://doi.org/10.11648/j.ajtte.20190404.11},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajtte.20190404.11},
      abstract = {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.},
     year = {2019}
    }
    

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  • TY  - JOUR
    T1  - Experimental Validation for Globally Optimized  Tractor-Trailer Base Flaps
    AU  - Jacob Andrew Freeman
    AU  - Mark Franklin Reeder
    AU  - Anna Christine Demoret
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    N1  - https://doi.org/10.11648/j.ajtte.20190404.11
    DO  - 10.11648/j.ajtte.20190404.11
    T2  - American Journal of Traffic and Transportation Engineering
    JF  - American Journal of Traffic and Transportation Engineering
    JO  - American Journal of Traffic and Transportation Engineering
    SP  - 103
    EP  - 117
    PB  - Science Publishing Group
    SN  - 2578-8604
    UR  - https://doi.org/10.11648/j.ajtte.20190404.11
    AB  - 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.
    VL  - 4
    IS  - 4
    ER  - 

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Author Information
  • Department of Aeronautics and Astronautics, Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio, USA

  • Department of Aeronautics and Astronautics, Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio, USA

  • Department of Aeronautics and Astronautics, Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio, USA

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