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Aerodynamic performance of a drag reduction device on a full-scale tractor/trailerThe effectiveness of an aerodynamic boattail on a tractor/trailer road vehicle was measured in the NASA Ames Research Center 80- by 120-Foot Wind Tunnel. Results are examined for the tractor/trailer with and without the drag reduction device. Pressure measurements and flow visualization show that the aerodynamic boattail traps a vortex or eddy in the corner formed between the device and the rear corner of the trailer. This recirculating flow turns the flow inward as it separates from the edges of the base of the trailer. This modified flow behavior increases the pressure acting over the base area of the truck, thereby reducing the net aerodynamic drag of the vehicle. Drag measurements and pressure distributions in the region of the boattail device are presented for selected configurations. The optimum configuration reduces the overall drag of the tractor/trailer combination by about 10 percent at a zero yaw angle. Unsteady pressure measurements do not indicate strong vortex shedding, although the addition of the boattail plates increases high frequency content of the fluctuating pressure.
Document ID
19920057348
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Lanser, Wendy R.
(NASA Ames Research Center Moffett Field, CA, United States)
Ross, James C.
(NASA Ames Research Center Moffett Field, CA, United States)
Kaufman, Andrew E.
(Continuum Dynamics, Inc. Princeton, NJ, United States)
Date Acquired
August 15, 2013
Publication Date
September 1, 1991
Subject Category
Engineering (General)
Report/Patent Number
SAE PAPER 912125
Accession Number
92A39972
Distribution Limits
Public
Copyright
Other

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