WIND-TUNNEL STUDY OF THE EFFECT OF GAP FLOW AND GAP SEALS ON THE AERODYNAMIC DRAG OF TRACTOR-TRAILER TRUCKS

The effect of gap width on the aerodynamic drag of a cab-over-engine tractor-trailer combination has been investigated for full-scale gap widths ranging from 0.61 m (24 inches) to 1.83 m (72 inches) over a yaw angle range of 0 to 20 degree. The average drag on the vehicle was found to increase from 0 to 12 percent as the gap width increased from 0.61 m to 1.83 m. Drag reductions were found when a vertical seal was placed along the vehicle centerline between the tractor and the trailer. The effect of vehicle configuration on gap seal effectiveness was evaluated for a gap width of 1.3 m (51 inches) using models of six different tractors and two different trailers. The average drag coefficient reductions that were found ranged from 0.04 to 0.09 with 75 percent of the data being either 0.05 or 0.06. It is shown that the use of gap seals on the nearly half-million vehicles which comprise the nation's long-haul trucking fleet can result in the conservation of about 1.7 X 10 to 9th power liters (0.5 X 10 to 9th power gal) of motor fuel each year.

• Supplemental Notes:
  • Prepared for meeting held November 27 to December 2, 1977.
• Corporate Authors:

  American Society of Mechanical Engineers

  Two Park Avenue
  New York, NY  United States  10016-5990
• Authors:
  • Buckley Jr, F T
  • Marks, C H
• Publication Date: 1977

Media Info

• Features: References;
• Pagination: 8 p.

Subject/Index Terms

• TRT Terms: Aerodynamics; Drag; Flow; Fuel conservation; Fuel consumption; Seals (Devices); Securing and joining equipment; Tractor trailer combinations; Trailers; Trucks; Width; Wind tunnels
• Subject Areas: Energy; Highways; Motor Carriers; Safety and Human Factors;

Filing Info

• Accession Number: 00176610
• Record Type: Publication
• Source Agency: Engineering Index
• Report/Paper Numbers: ASME 77-WA-FE-23
• Files: TRIS
• Created Date: Jul 29 1978 12:00AM