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

TL;DR

This study investigates the complex chiral flow behavior in a binary mixture of air-fluidized disks with opposite blade tilts, revealing vortex inversion phenomena and diverse fluid dynamics.

Contribution

It introduces experimental analysis of chiral flow in a binary active disk mixture, highlighting vortex inversion and phase behavior not previously documented.

Findings

Identification of chiral flow with large vortices

Observation of vortex vorticity inversion under certain densities

Diverse fluid dynamic regimes observed

Abstract

We study, experimentally, 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 blades tilt angle, which is rotated by 180o in the second species. We analyze 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 report, for certain ranges of relative particle density of each species, inversion of the vorticity of this vortex. We discuss on the possible mechanisms behind these chiral flow transitions.