Topology of thermocapillary-driven convection and induced coherent structures by low-Stokes-number particles in closed system with free surface

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K20977
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 19:Fluid engineering, thermal engineering, and related fields
• Research Institution: Tokyo University of Science
• Principal Investigator: UENO ICHIRO 東京理科大学, 理工学部機械工学科, 教授 (40318209)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: 表面張力差駆動対流 / コヒーレント構造 / 低ストークス数粒子

Outline of Final Research Achievements

We investigate the coherent structures by low-Stokes-number particles suspended in high-aspect-ratio liquid bridges of high-Prandtl number via microgravity and terrestrial experiments. We especially focus on the structure by the suspended particle accumulation, or, the particle accumulation structure (PAS), of m = 1 in azimuthal wave number emerged in the traveling-wave-type time-dependent convection. We also investigate multicellular convective structures induced in free liquid films by thermocapillary effect. A thin film of high-Prandtl-number liquid is prepared in a rectangular aperture of the order of 0.1 mm in thickness sustained by its surface tension. The multicellular structure is established in the free liquid films. The cell number increases in a stepwise manner as the liquid-film width increases. It is found that another pair of the cells always newly emerges when the cell number increases.

Free Research Field

界面熱流体力学

Academic Significance and Societal Importance of the Research Achievements

閉空間内対流場における秩序構造、さらにその対流場による微小粒子の集合・分散の制御を実現する。Kolmogorov-Arnold-Moser環状体と高い相関を有するコヒーレント構造の発現条件やその空間構造の定量化、コヒーレント構造を構成する微小粒子の時空間挙動の解明により学術的貢献に資するとともに、結晶成長過程における結晶核の集合・分散制御や、汚染源となる微小物体の効率的排除機構の開発等に貢献する。