A discussion of the basic elements of bluff body drag, as it relates to truck air resistance is given. The concept of a dragless forebody is introduced. It is shown that this dragless state can nearly be achieved with a lip-like device on the front face of the van. The shielding effect of one body ahead of another is described, and the deleterious effects of crossflow in the gap between the bodies is discussed. In particular, it is shown that some add-on devices are particularly susceptible to crosswind flows and lose effectiveness at a few degrees of yaw. Two devices, one, the lip, for the front face of the van body, and the other, the perforated screen for tractor mounting, have been road tested and give very substantial savings in aerodynamic drag coefficients, exceeding 30% in both cases. The fuel savings associated with such deivces depend upon payload, speed, etc, but can be as much as 60% of the aerodynamic drag saving.

  • Supplemental Notes:
    • Prepared for meeting August 11-14, 1975.
  • Corporate Authors:

    Society of Automotive Engineers (SAE)

    400 Commonwealth Drive
    Warrendale, PA  United States  15096
  • Authors:
    • Lissaman, PBS
  • Publication Date: 1975-8

Media Info

  • Pagination: 10 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00128874
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Report/Paper Numbers: SAE #750702 Preprint
  • Files: TRIS
  • Created Date: Feb 4 1976 12:00AM