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Boundary-layer control of bluff bodies with application to drag reduction of tractor-trailer truck configurations Ying, Bin
Abstract
Effectiveness of two fundamentally different concepts of boundary-layer control for the drag reduction of bluff bodies is studied experimentally. The methods are: (i) Moving Surface Boundary-layer Control (MSBC) involving momentum injection through one or more rotating elements (light hollow cylinders); and (ii) tripping of the boundary-layer using judiciously located fences to interrupt pressure recovery. Wind tunnel tests with a two-dimensional wedge airfoil model suggest that injection of momentum can significantly delay separation of the boundary-layer resulting in a narrow wake and the associated reduction in the pressure drag. It also leads to a substantial increase in the lift at a given angle of attack resulting in a dramatic rise in the lift to drag ratio, from 2 to 80, under optimum conditions. Effectiveness of the momentum injection process is primarily governed by the gap-size, cylinder surface roughness and the ratio of the cylinder surface velocity (Uc) to the free stream velocity (U). A three-dimensional model of a rectangular prism and a 1/12 scale model of a typical tractor-trailer truck configuration show that both the MSBC and fence approaches are promising in reducing the aerodynamic resistance. A kit configuration is proposed for ease of implementation of the concepts on new and existing trailers. Road tests with a full scale cube-truck are recommended to assess effectiveness of the boundary-layer control procedures in reducing the drag during highway conditions.
Item Metadata
Title |
Boundary-layer control of bluff bodies with application to drag reduction of tractor-trailer truck configurations
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1991
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Description |
Effectiveness of two fundamentally different concepts of boundary-layer control for the drag reduction of bluff bodies is studied experimentally. The methods are:
(i) Moving Surface Boundary-layer Control (MSBC) involving momentum injection through one or more rotating elements (light hollow cylinders); and (ii) tripping of the boundary-layer using judiciously located fences to interrupt pressure recovery. Wind tunnel tests with a two-dimensional wedge airfoil model suggest that injection of momentum can significantly delay separation of the boundary-layer resulting in a narrow wake and the associated reduction in the pressure drag. It also leads to a substantial increase in the lift at a given angle of attack resulting in a dramatic rise in the lift to drag ratio, from 2 to 80, under optimum conditions. Effectiveness of the momentum injection process is primarily governed by the gap-size, cylinder surface roughness and the ratio of the cylinder surface velocity (Uc) to the free stream velocity (U). A three-dimensional model of a rectangular prism and a 1/12 scale model of a typical tractor-trailer truck configuration show that both the MSBC and fence approaches are promising in reducing the aerodynamic resistance. A kit configuration is proposed for ease of implementation of the concepts on new and existing trailers. Road tests with a full scale cube-truck are recommended to assess effectiveness of the boundary-layer control procedures in reducing the drag during highway conditions.
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Extent |
9773015 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2008-09-16
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0081045
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1992-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.