| Project/Area Number |
19K04180
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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 | Okinawa Institute of Science and Technology Graduate University |
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Principal Investigator |
Chakraborty Pinaki 沖縄科学技術大学院大学, 流体力学ユニット, 教授 (90745928)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2021: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2020: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
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| Keywords | Taylor-Couette flow / small-scale universality / energy spectrum / Taylor-Couette flows / turbulent energy spectra / Turbulence / Small-scale universality / Energy spectrum |
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| Outline of Research at the Start |
Recent experiments on Taylor-Couette (TC) flows pose a major challenge to the fundamental concept of universality in turbulent flows. However, because the experiments did not focus on the small scales, we propose to undertake a first study to systematically examine the statistical structure of small scales in turbulent TC flows. With a focus on performing critical tests of small-scale universality, we plan to conduct experiments using the recently built OIST-TC setup in our laboratory. We expect our results to shed completely new light on the understanding of rotating turbulent flows.
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| Outline of Final Research Achievements |
A fundamental concept in the theory of turbulent flows is "small-scale universality". It posits that the statistical structure of the small scales in all turbulent flows is universal, irrespective of the flow. Results from previous studies on turbulent Taylor-Couette (TC) flow suggest that its spectral structure violates small-scale universality. In this research project, we have conducted measurements of the energy spectra in turbulent TC flow using unique flying hot-wire experiments in the OIST-TC setup. In contrast with previous studies, our results show that the spectral structure of small scales in turbulent TC flow is in excellent accord with small-scale universality.
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| Academic Significance and Societal Importance of the Research Achievements |
Our study shows that, contrary to what is widely believed to be the case, small-scale universality prevails in turbulent Taylor-Couette (TC) flow, with the implication that Kolmogorov's theory can be used to elucidate the mysteries of turbulent TC flow.
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