Large scale zigzag pattern emerging from circulating active shakers

Abstract

We report the emergence of large zigzag bands in a population of reversibly actuated magnetic rotors that behave as active shakers, namely squirmers that shake the fluid around them without moving. The shakers collectively organize into dynamic structures displaying self-similar growth, and generate topological defects in form of cusps that connect vortices of rolling particles with alternating chirality. By combining experimental analysis with particle-based simulation, we show that the special flow field created by the shakers is the only ingredient needed to reproduce the observed spatiotemporal pattern. We unveil a self-organization scenario in a collection of driven particles in an viscoelastic medium emerging from the reduced particle degrees of freedom, as here the frozen orientational motion of the shakers.

References in corpus (4)

• The hydrodynamics of swimming microorganisms
• Theory of swimming filaments in viscoelastic media
• Optical tweezers microrheology maps the dynamics of strain-induced local inhomogeneities in entangled polymers
• Colloidal Surfaces with Boundaries, Apex Boojums and Nested Elastic Self-Assembly of Nematic Colloids

Cited by in corpus (1)

• Bidirectional Zigzag Growth from Clusters of Active Colloidal Shakers