Dynamics of inert spheres in active suspensions of micro-rotors

Abstract

Inert particles suspended in active fluids of self-propelled particles are known to often exhibit enhanced diffusion and novel coherent structures. Here we numerically investigate the dynamical behavior and self-organization in a system consisting of passive and actively rotating spheres. The particles interact through direct collisions and the fluid flows generated as they move. In the absence of passive particles, three states emerge in a binary mixture of spinning spheres depending on particle fraction: a dilute gas-like state where the rotors move chaotically, a phase-separated state where like-rotors move in lanes or vortices, and a jammed state where crystals continuously assemble, melt and move (K. Yeo, E. Lushi, and P. M. Vlahovska, Phys. Rev. Lett. 114, 188301 (2015)). Passive particles added to the rotor suspension modify the system dynamics and pattern formation: while states identified in the pure active suspension still emerge, they occur at different densities and mixture proportions. The dynamical behavior of the inert particles is also non-trivially dependent on the system composition.

arXiv comment8 pages, 7 figures

References in corpus (22)

• Athermal Phase Separation of Self-Propelled Particles with no Alignment
• Optical alignment and spinning of laser-trapped microscopic particles
• Emergence of macroscopic directed motion in populations of motile colloids
• Dynamic clustering in active colloidal suspensions with chemical signaling
• Fluid dynamics of bacterial turbulence
• Fluid Flows Created by Swimming Bacteria Drive Self-Organization in Confined Suspensions
• Dancing Volvox: Hydrodynamic Bound States of Swimming Algae
• Activity-induced phase separation and self-assembly in mixtures of active and passive particles
• Phase separation and rotor self-assembly in active particle suspensions
• Emergent vortices in populations of colloidal rollers
• Enhanced diffusion due to active swimmers at a solid surface
• Emergent collective phenomena in a mixture of hard shapes through active rotation
• Stirring by squirmers
• Collective dynamics in a binary mixture of hydrodynamically coupled micro-rotors
• Enhanced diffusion of nonswimmers in a three-dimensional bath of motile bacteria
• Diffusion of an ellipsoid in bacterial suspensions
• Particle diffusion in active fluids is non-monotonic in size
• Fluid transport by individual microswimmers
• Purely hydrodynamic ordering of rotating disks at a finite Reynolds number
• Cooperative Self-Propulsion of Active and Passive Rotors
• Periodic and chaotic orbits of plane-confined micro-rotors in creeping flows
• Motility versus fluctuations in mixtures of self-propelled and passive agents

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