Long-term Behaviors of a Single Particle Forming a Coherent Structure in Thermocapillary-driven Convection in Half-zone Liquid Bridge of High Prandtl-number Fluid

Abstract

We experimentally investigate behaviors of a single spherical particle in a half-zone liquid bridge induced by the thermocapillary effect. It has been indicated that suspended particles show unique structures in time-dependent traveling flow state. This phenomenon is called ‘particle accumulation structure (PAS).’ In order to understand correlation between the identical particle motion and the coherent structures by the particles, we focus on a single particle behavior to illustrate the spatio-temporal correlation between PAS itself and individual particles on PAS. We indicate the Poincaré section for the particle forming PAS and that forming the toroidal core by preparing a thin light sheet. Through a long-period observation of the turnover motion of individual particle, we make comparison with the proposed topological flow fields accompanying with so-called Kolmogorov-Arnold-Moser (KAM) tori. The present work is conducted as a ground-based research for coming on-orbit international collaborative experiments aboard the Japanese Experiment Module ‘Kibo’ in the International Space Station by the project of Japanese-European Research Experiment on Marangoni Instability (JEREMI).