2001 Fiscal Year Final Research Report Summary
Dynamics and Statistics of Worms around a Calumnar Vortex
| Project/Area Number |
12640387
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
物理学一般
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| Research Institution | The University of Electro-Communications |
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Principal Investigator |
MIYAZAKI Takeshi Faculty of Electric Communications, The University of Electro-Communications, Prof., 大学院・電気通信学研究科, 教授 (50142097)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Turbulence / Ordered Vortex / Fine Eddies (Worms) / Blocking Effect / Vortex Wave / Velocity Correlation |
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| Research Abstract |
The interaction between a columnar vortex and external turbulence is investigated numerically. A Lamb-Oseen vortex is immersed into initially isotropic homogeneous turbulence, which, itself, is produced numerically by a direct numerical simulation of decaying turbulence. The formation of inhomogeneous fine turbulent eddies around the columnar vortex and the vortex-core deformations are studied in detail, by visualizing the flow field. The initially random turbulent eddies (worms) are wrapped around the columnar vortex, and become like vortex rings (or sprirals). Statistical quantities, such as two-point-energy-spectrum and two-point-enstrophy spectrum, are evaluated by averaging 20 realizations and compared with the theoretical predictions by a. rapid distortion theory (RDT). The axial velocity correlation dominates near the vortex surface, whereas the radial velocity correlation becomes larger, where the worms are wrapped. If the columnar vortex is strong compared with the external turbulence, external velocity disturbances are blocked by the vortex and they cannot penetrate into the vortex core directly, whereas various types of vortex waves (Kelvin waves) are excited by the external pressure disturbances.
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Research Products
(4 results)
