2023 Fiscal Year Final Research Report
Elucidation of mechanism of local anisotropic energy transfer in transitional region between weak and strong turbulence in real and wavenumber spaces
| Project/Area Number |
21K03883
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 19010:Fluid engineering-related
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| Research Institution | Tokyo Denki University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
高岡 正憲 同志社大学, 理工学部, 教授 (20236186)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | 非等方乱流 / 強弱乱流 / 非等方エネルギー輸送 / 準地衡流乱流 / 成層乱流 / 臨界平衡 |
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| Outline of Final Research Achievements |
In previous studies, to identify the energy flux in coexistence of multiple kinds of turbulence, energy-flux vector in anisotropic turbulence was proposed by assuming the locality and efficiency of the energy transfer in the wavenumber space. In two-dimensional quasi-geostrophic turbulence, the local flux agrees with the critical balance, which conjectures that the energy is transferred along the separating wavenumbers in the coexistence of weak and strong turbulence. It is found that the local energy flux in stratified turbulence is consistent with the induced diffusion which is obtained in the limit of the anisotropy and the nonlocality in the weak turbulence theory, though the locality is assumed in our method.
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| Free Research Field |
流体力学
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| Academic Significance and Societal Importance of the Research Achievements |
先行研究にて提案された非等方乱流のエネルギーフラックスベクトルの同定手法を準地衡流乱流と成層乱流に適用し、成層乱流、準地衡流乱流、先行研究で行った回転乱流の3つの代表的な非等方乱流系のいずれにおいても弱乱流理論や臨界平衝仮説と整合するエネルギーフラックスを定量的に得ることができた。特に成層乱流において弱乱流理論によって共鳴相互作用の非等方かつ非局所の極限で誘導拡散によるエネルギー輸送が卓越すること知られているが、局所性を仮定したにもかかわらずこれと矛盾しないエネルギーフラックスが得られたことは、局所エネルギーフラックスの有用性を強く示唆している。
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