2023 Fiscal Year Final Research Report
Common Properties of Gravitational Instability in Liquid Systems and Granular Systems
| Project/Area Number |
20K14379
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 13010:Mathematical physics and fundamental theory of condensed matter physics-related
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| Research Institution | Nippon Institute of Technology (2022-2023)
Tokyo University of Agriculture and Technology (2021)
Tokyo Metropolitan University (2020) |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2024-03-31
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| Keywords | 粉体流動 / 高分子ゲル / Rayleigh-Taylor不安定性 |
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| Outline of Final Research Achievements |
Focusing on the phenomenon of gravitational instability occurring when granular materials are dropped under gravity, research was conducted to elucidate the parallels between this phenomenon and the well-known Rayleigh-Taylor instability in liquid systems. The pattern of gravitational instability formed during the liquid transition was experimentally investigated using physical gels, which can undergo a reversible solid-liquid transition through heating or cooling, as a model similar to a granular system. The solid-liquid transition of the physical gel initiated sequentially from the lower surface due to heat conduction, leading to destabilization at the transition point and the formation of a fingering pattern. This pattern closely resembled that observed in gravitational instability phenomena in granular systems. Systematic experiments demonstrated that the dominant parameter for the destabilization dynamics is the width of the upper flowable region, revealing a quantitative link.
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| Free Research Field |
ソフトマター物理学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究課題によって，不安定化ダイナミクスを支配するパラメータが，上層の流動可能領域幅であることを突き止め，流体系と粉体系の重力不安定性現象との間に明確なリンクがあることを見出した．この共通性は，粉体のかかわる自然災害（例えば液状化現象や地震，粉塵爆発等）や，粉体を使用した製品の開発・製造等の工業プロセスにおける問題点の解決，さらに，粉体の流動制御技術など，幅広い分野への応用が期待できると考えている．
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