2003 Fiscal Year Final Research Report Summary
Turbulent Elementary Votrices and New Development in Theory, Predicition, and control of Turbulence
| Project/Area Number |
12125101
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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. Engineerig, Professor, 工学研究科, 教授 (70093234)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAUCHI Toshio Tokyo Institute of Technology, Department of Mechanical and Aerospace Engineering, Professor, 工学研究科・機械宇宙学科, 教授 (50016664)
NIINO Hiroshi University of Tokyo, Ocean Research Institute, Professor, 海洋研究所, 教授 (90272525)
NISHIOKA Michio Osaka Prefecture University, Depart of Aerospace Engineering, Professor, 工学研究科・航空宇宙工学, 教授 (60081444)
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)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Turbulence / Elementary Vortex / Turbulence Theory / Turbulence Prediction / Turbulence Control |
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| Research Abstract |
The elementary vortices are the smallest coherent structures in turbulence. Their physical characteristics and dynamical roles in turbulence have been clarified by the theory, the experiment, and the computer simulation in various kinds of turbulence realized in nature, laboratories, and computers. The elementary vortices exhibit common physical characteristics independent of the kinds of turbulence, that is, a tubular central vortex is surrounded by spiral vortex layers, the diameter and swirl velocity obey the Kolmogorov scaling laws but the length of the vortex extends to the large scales of turbulence, the vortices make groups and are localized in space, and many elementary vortices tend to approach in an anti-parallel manner and enhance the mixing ability. As engineering and practical applications, the large-eddy-simulation model based on the elementary vortices, the active feedback control of the wall turbulence by manipulating the elementary vortices have been developed, and the mechanisms of the enhancement of supersonic mixing combustion by introducing the longitudinal vortices and the generation of tornados as the large-scale coherent vortex have been clarified. Furthermore, the unstable periodic motions (spatio-temporal coherent structure as the skeleton of turbulence) accompanying regeneration of elementary vortices have been discovered in the Couette turbulence. The concept and the dynamics of turbulent elementary vortices established in the present research project shall be useful for the future turbulence research.
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