| 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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| Co-Investigator(Kenkyū-buntansha) |
山本 稀義 航空宇宙技術研究所, 流体科学総合研究グループ, 研究グループ長
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | Turbulence / Ordered Vortex / Fine Eddies (Worms) / Blocking Effect / Vortex Wave / Velocity Correlation / 乱流微細渦構造 / 大振幅渦波 / Blocking effect / エネルギーカスケード / 直接数値計算 / RDT / スカラー輸送 |
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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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