Experiments and Computer Simulations on Aerodynamic Drag Reduction of Light Vehicle-Trailer Systems

  • Author / Creator
    Boyer, Henry R.
  • Wind-tunnel experiments and Computational Fluid Dynamics (CFD) were performed to study the effect a deflector had on the flow and drag force associated with a 2010 F-150 truck and cargo trailer (Light Vehicle-Trailer System - LVTS). Image Correlation Velocimetry (ICV) on smokewire streaklines measured the velocity field on the model mid-plane. CFD was used to elucidate the flow, calculate the drag force, and study the effects of a moving ground-plane and blockage. The drag was reduced by approximately 13% at a Re of 14,900 with a moving ground-plane, and 17% without. Experiments suggested that the large difference in Re between wind-tunnel and the full-scale 5 million is not expected to significantly diminish the full-scale relevance of the drag results. One low Re effect was the presence of a separation bubble on the hood of the tow vehicle whose size reduced with an increase in Re. Three other characteristic flow patterns were identified: separation off the lead vehicle cab, stagnation of the free-stream on the trailer face for the no-deflector case, and subsequent separation at the trailer front corner. Comparisons of the ICV and CFD results with no deflector indicated good agreement, particularly in the direction of the velocity vectors. The ICV method under-evaluated the speed of the flow by up to 15%. The smoke streaklines and CFD streamlines agreed well for the no deflector case. However, for the deflector case, the CFD found an entirely different topological solution absent in the experiment. A pair of vertically-oriented vortices were found, wrapped around the front of the trailer on the mid-plane.

  • Subjects / Keywords
  • Graduation date
    Fall 2015
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.