Experimental study on behaviors of low-Stokes number particles in weakly chaotic structures induced by thermocapillary effect within a closed system with a free surface

Attractors for the motion of a finite-size particle in a two-sided lid-driven cavity

“…For dilute suspensions the attractors can be populated by several or even many finite-size particles. Such PAS have been observed in thermocapillary flows (Schwabe et al 2007;Toyama et al 2017;Watanabe et al 2018;Oba et al 2019). The present experimental results have shown that the transfer of particles to attractors by the finite-size boundary interaction is a more general concept and can lead to finite-size coherent structures (Romanò et al 2019b).…”

Particle accumulation structures in noncylindrical liquid bridges under microgravity conditions

“…Along these lines, as an example, it is also worth mentioning that other researchers ([18], [34], and [40] and [41]) have reported on the existence of an alternate, less ordered state, generally referred to as the "toroidal core" given the tendency of particles to cluster where the fluid vorticity takes relatively high values. Romano and Kuhlmann [36] could show numerically that this peculiar behavior should be regarded as an intermediate stage of evolution.…”

“…Though this numerical approach should clearly be regarded as a simplification of reality (obviously this scheme cannot describe particle interaction when accumulation takes place), it has enjoyed a widespread use in the literature for the study of PAS ([3-5], [10], [29], [34][35][36], [43], [48]) . A justification or rationale for such a practice can be found in available experimental observations or data ( [2], [6][7][8][9], [19], [37][38][39][40][41], [44]). Indeed, experiments dealing with a variety of fluids and particle types have shown that once particles enter the attractor (the KAM torus), they can no longer leave it (inter-particle forces are not sufficiently strong to allow particles to get away from the attractor).…”

“…Romano and Kuhlmann [36] could show numerically that this peculiar behavior should be regarded as an intermediate stage of evolution. Oba et al [41] indicated experimentally that the particles on the core exhibit chaotic motions. Lappa [42] found that the application of high-frequency high-amplitude vibrations along the axis of the liquid bridge could make this peculiar state stable.…”

On the influence of gravity on particle accumulation structures in high aspect-ratio liquid bridges

“…2017; Oba et al. 2019; Yamaguchi, Hori & Ueno 2019). In particular, one of the properties that has received significant interest is the so-called number of loops (), i.e.…”