On the Mechanisms of Directed Propagation of Suspension Microdroplets with Active Microparticles

Abstract

This article presents the results of a numerical study of hydrodynamic flows arising in suspension droplets containing active microparticles. Using a two-phase mathematical model that incorporates a Lagrangian description of individual particle motion and an Eulerian description of the carrier fluid flow, the influence of droplet geometry, as well as the nature and intensity of the active force, on the formation of self-consistent flows is investigated. The model resolves key interaction mechanisms: the autonomous motion of particles and their hydrodynamic feedback with the liquid. It is shown that in a spherical droplet under a randomly directed active force acting on each particle, a stable large-scale flow structure in the form of a spindle-shaped vortex encompassing the entire liquid volume is formed. In the case of a directed active force, a toroidal flow emerges, causing a pronounced displacement of the system’s center of mass, which can, in turn, serve as a mechanism for the directed motion of the suspension droplet as a whole. It is established that the nature and topology of the internal flows significantly depend on the kinetic parameters of the active force, with a clear transition observed from the initial chaotic particle motion to an organized collective dynamic state. The obtained results allow for the identification of characteristic hydrodynamic regularities and flow patterns underlying the self-propulsion mechanisms of active suspensions and establish a basis for analyzing more complex phenomena in microfluidics

The work was supported by the Russian Science Foundation (project no. 24-12-00345, https://rscf.ru/project/24-12-00345)

Please cite this article in English as:

Yakovenko I.S. On the mechanisms of directed propagation of suspension microdroplets with active microparticles. Herald of the Bauman Moscow State Technical University, Series Natural Sciences, 2026, no. 4 (127), pp. 4--20 (in Russ.). EDN: QIVOFV

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