| Project/Area Number |
09450075
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | Nagoya University |
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Principal Investigator |
HASEGAWA Yutaka Nagoya University, Graduate School of Engineering, Professor, 工学研究科, 教授 (90023192)
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| Co-Investigator(Kenkyū-buntansha) |
ASAKURA Eiji Nagoya University, Graduate School of Engineering, Research Associate, 工学研究科, 助手 (90135327)
長谷川 豊 名古屋大学, 工学研究科, 助教授 (20198732)
KIKUYAMA Koji Nagoya University, Graduate School of Engineering, Associate Professor (90023192)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥14,700,000 (Direct Cost: ¥14,700,000)
Fiscal Year 1998: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1997: ¥12,300,000 (Direct Cost: ¥12,300,000)
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| Keywords | Boundary Layr / Transition / Coriolis Force / Centrifugal Force / Wall Curvature / Velocity Distribution / Goertler Vortex / Tollmien-Schlichting Waves |
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| Research Abstract |
Stability of laminar boundary layer having a mean velocity of Blasius type was studied by solving numerically the perturbation equations when the boundary layer is subject to the centrifugal force due to the streamline curvature and the Coriolis force due to the system rotation and the following results have obtained theoretically.
(1) When the Coriolis force acts toward the concave surface, the boundary layer is more unstable and vortices are generated at a lower value of wall curvature. With larger Coriolis force, Goetler vortices would appear even on a convex surface.
(2) In a lamianr boundary layer with an adverse pressure gradient occurrence of the Goertler vortices are promoted by the Coriolis force acting toward the wall surface.
In order to verify the calculation results, a curved channel whose radius of curvature and aspect ratio of the channel section are equal to 1000mm and 8, respectively, was made and mounted on a rotating table of 3000mm diameter. Air was introduced through an two-dimensional nozzle and exhaused azially theou the axis. The natue of the boundary layer on a convex and concave surfaces were ezmained on a thin durved plate inserted along the centerline of the channel using a hot wire probe.
Experiments were carried out in a stationary state of the channel at the Reynolds numbers of Re = 40,000 and 80,000. The following results were obtained.
The centrifugal force causes a large effect on the development of the boundary layer and accelerate the transition to the turbuent state in the concave side but the force suppresses the turbulent motion in the boundary layer on the convex side and deleys the transition to the turbulent state.
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