Chiral flow in a binary mixture of two-dimensional active disks

Abstract

In this article, we, experimentally, studied the dynamics of a binary mixture of air-fluidized disks. The disks are chiral since they incorporate a set of blades with constant tilt. Both species are identical except for their blade tilt angle, which is rotated by 180° in the second species. We analyzed the phase behavior of the system. Our analysis reveals a wide range of different fluid dynamics, including chiral flow. This chiral flow features in its base state a large vortex. We reported, for certain ranges of relative particle density of each species, inversion of the vorticity of this vortex. We discussed the possible mechanisms behind these chiral flow transitions.

Density Mediated Spin Correlations Drive Edge to Bulk Flow Transition in Active Chiral Matter

“…While collections of granular rods can self-assemble to form chiral structures which spin collectively [16], particles with tilted legs and bumpy sides, which promote frictional particle-particle interactions, have been demonstrated to spin, self-organize, and give rise to further collective motion [17][18][19]. Particle interactions occur only during contact and present the opportunity to investigate density effects over a wide range of area fractions, in contrast to systems in which secondary flows in the interstitial medium can give rise to attraction and other system-specific effects [11,20].…”