{"id":{"repo_id":"ubc","oai_identifier":"oai:circle.library.ubc.ca:2429/2106"},"canonical_url":"https://search.dev.ndltd.org/etd/ubc/oai:circle.library.ubc.ca:2429/2106","repository":{"repo_id":"ubc","name":"University of British Columbia","base_url":"http://circle.library.ubc.ca/oai/request"},"display":{"title":"Boundary-layer control of bluff bodies with application to drag reduction of tractor-trailer truck configurations","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.","abstract_html":"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.","abstract_has_math":false,"creators":["Ying, Bin"],"institution":"University of British Columbia","degree_name":"Master of Applied Science - MASc","degree_level":"master's","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1991,"date_issued":"1991","date_published":"1991","updated_at":"2026-07-24T05:07:37Z","subjects":[],"languages":["eng"],"rights":["For non-commercial purposes only, such as research, private study and education. 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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."]},{"key":"dc:format","label":"Dc Format","values":["9773015","application/pdf"]},{"key":"dc:title","label":"Title","values":["Boundary-layer control of bluff bodies with application to drag reduction of tractor-trailer truck configurations"]}]}],"canonical_facts":{"dc:creator":["Ying, Bin"],"dc:date":["1991"],"dc: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. 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