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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/193867
Hydrodynamic and geometric effects in the sedimentation of model run-and-tumble microswimmers
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The sedimentation process in an active suspension is the result of the competition between gravity and the autonomous motion of particles. We carry out simulations of run-and-tumble squirmers that move in a fluid medium, focusing on the dependence of the non-equilibrium steady state on the swimming properties. We find that for large enough activity, the density profiles are no longer simple exponentials; we recover the numerical results through the introduction of a local effective temperature, suggesting that the breakdown of the Perrin-like exponential form is a collective effect due to fluid-mediated dynamic correlations among particles. We show that analogous concepts can also fit the case of active non-motile particles, for which we report the first study of this kind. Moreover, we provide evidence of scenarios where the solvent hydrodynamics induces non-local effects which require the full three-dimensional dynamics to be taken into account in order to understand sedimentation in active suspensions. Finally, analyzing the statistics of the orientations of microswimmers, the emergence of a height-dependent polar order in the system is discussed.
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SCAGLIARINI, Andrea and PAGONABARRAGA MORA, Ignacio. Hydrodynamic and geometric effects in the sedimentation of model run-and-tumble microswimmers. Soft Matter. 2022. Vol. 18, num. 2407-2413. ISSN 1744-683X. [consulted: 13 of June of 2026]. Available at: https://hdl.handle.net/2445/193867