Dynamics of two interacting drops in a microfluidic confinement under imposed temperature gradient
Year: 2026
Type: article
Abstract: A tiny drop of one liquid, suspended within another, is known to be set into motion aligned with an imposed thermal gradient, as influenced by thermocapillary action stemming from the gradients in interfacial tension due to the local variations in temperature. In real-world situations, however, such drops do not remain in isolation, as they interact with their neighboring entities, including other drops in proximity as well as a nearby solid boundary, setting up a complex interplay between the confinement-mediated interactions and the three-dimensional nature of the drop dynamics. In this study, we present numerical solutions for the migration dynamics of a tightly confined drop couple, incorporating deformable interfaces, and Marangoni effects in the presence of dynamically evolving thermocapillary stresses induced by an imposed uniform temperature gradient. Unlike prior investigations, our work delineates a parameter that highlights the influence of the droplet surface tension forces towards orchestrating non-trivial features of drop migration, as dictated by an intricate coupling of the thermal and flow fields amidst the interferences of the domain boundaries. The study reveals that the droplets deform and undeform in an unique manner as compared to the characteristics evidenced by previously reported studies, causing a distortion of the local thermal fields around them. This, in turn, leads to changes in the local thermocapillary stress, and the consequent alteration in the drop velocities is shown to govern their migration in a distinctive manner, presenting unique signatures as compared to more restrictive scenarios studied previously. Non dimensional parameters like the conductivity ratio between the droplet and carrier phases along with the domain confinement are shown to modify the flow physics so as to either accentuate or moderate the influence of surface tension forces on drop migration. These findings hold significance in designing thermocapillary-driven micro-confined systems for controlling drop trajectories under an imposed thermal field, bearing far-reaching implications in a plethora of overarching applications ranging from drop microfluidics to space technology.
Source: Fluid Dynamics Research
Authors: Sayak Ray, Sudipta Ray, Suman Chakraborty
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,325
OpenAlex ID: W4417245885
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