2003 Fiscal Year Final Research Report Summary
Structure and Dynamics of Turbulent Elementary Vortices
| Project/Area Number |
12125204
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Kyoto University (2003)
National Institute for Fusion Science (2000-2002) |
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Principal Investigator |
KIDA Shigeo Kyoto University, Department of Engineering, Professor, 工学研究科, 教授 (70093234)
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| Co-Investigator(Kenkyū-buntansha) |
TOH Sadayoshi Kyoto University, Department of Physics, Associate Professor, 大学院・理学研究科, 助教授 (10217458)
MIYAZAKI Takeshi The University of Electro-Communications, Department of Mechanical Engineering and Intelligent Systems, Professor, 大学院・電気通信学研究科, 教授 (50142097)
MIURA Hideaki National Institute for Fusion Science, Associate Professor, 助手 (40280599)
GOTO Susumu National Institute for Fusion Science, Research Assistant, 助手 (40321616)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Turbulence / Elementary Vortex / Antiparallel Approach / Vortex Wave / Unstable Periodic Motion |
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| Research Abstract |
In the study of the basic properties of the elementary vortices, the spatial distribution and the Reynolds number dependence of their physical characteristics have been clarified quantitatively, suggesting that the elementary vortices may keep their dynamical importance at larger Reynolds numbers. An automatic chasing scheme of vortices has been developed to find the anti-parallel approach of vortices, which stretch the fluia lines and surfaces exponentially in time. The compressibility of fluids has been shown to induce vortex waves and to suppress the vortex growth. A new dynamo phenomenon by interactions between convection vortices and magnetic fields has been discovered in MHD turbulence. unstable periodic motions accompanying the generation and breakdown of the elementary vortices has been found in Couette turbulence. In the study of basic dynamical properties of the elementary vortices, the interaction of large-scale coherent vertical structures and turbulent field has been investigated with or without the axial flow in the coherent vortices. In the former case, fine scale vortices are generated and wrapped around the vortex surface, and axi-symmetric bending vortices are generated inside the coherent vortex. In the latter, on the other hand, vortex rings produced from the elementary vortices enhance the energy dissipation at the periphery of the vortex core. In a Poiseuille turbulence, longitudinal Vortex and streak structures have been observed in the outer layer like as in the inner layer.
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