Gravitational Instability in Liquid Systems and Granular Materials

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K23428
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0202:Condensed matter physics, plasma science, nuclear engineering, earth resources engineering, energy engineering, and related fields
• Research Institution: Tokyo University of Agriculture and Technology (2021); Tokyo Metropolitan University (2020); SALESIAN POLYTECHNIC (2019)
• Principal Investigator: Kobayashi Kazuya 東京農工大学, 工学(系)研究科(研究院), 特任助教 (00849474)
• Project Period (FY): 2019-08-30 – 2022-03-31
• Keywords: 粉体 / レイリーテイラー不安定性 / 非平衡

Outline of Final Research Achievements

Gravitational instability, which is a typical example of hydrodynamic instabilities, occurs due to density difference. When a heavy fluid lies over a light fluid in a constant gravitational field, fluctuations at the interface gradually increase and then macroscopic flows occur. The gravitational instability can be found not only in liquid-liquid interface but also in the gravitational settling of granular materials. However, the gravitational instability of liquid systems and granular systems have been discussed individually in most cases. We find a interesting relationship between the granular system and the physical gel. We also find that those behaviors are determined by the depth of the fluidization.

Free Research Field

ソフトマター物理学

Academic Significance and Societal Importance of the Research Achievements

本研究課題ではこれまで個別的に取り扱われることが多く，共通的性質は未解明のままであった粉体系の重力不安定性現象について，性質が類似している系として新たに物理ゲルに着目し，両者の類似性を系統的な実験を通して共通性を明らかにしている．今回明らかにした液体系および粉体系の重力不安定性現象の共通性は，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や粉体の制御技術など，物理学にとどまらない幅広い分野への応用が期待できると考えている．