Vortex formation of spherical self-propelled particles around a circular obstacle

Abstract

The vortex of spherical active Brownian particles around a circular obstacle.

Obstacle-induced giant jammed aggregation of active semiflexible filaments

“…Note that the vortex is always transient (no vortex is observed persisting more than five rounds in our simulations) in contrast to the vortex formed by ABPs. 41…”

“…Note that the vortex is always transient (no vortex is observed persisting more than five rounds in our simulations) in contrast to the vortex formed by ABPs. 41 A surprising finding is that, under certain conditions, APs pack tightly on the surface of the obstacle forming a stable GJA. For our finite system, almost all APs join the aggregate, i.e.…”

“…vortex. 41,43 The transporting behavior of active objects in media-usually mimicked by an ordered or a random array of obstacles-is rich and complex. For example, the movement of active objects may be smooth or impeded and even stopped or enhanced; there may exist an optimal direction for transportation.…”

“…40 Such obstacle-induced MIPS of active Brownian particles (ABPs) occurs at concentrations below the threshold value for MIPS in the bulk. 41 Collisions and pushes between particles cause collective rotation of the aggregate around the obstacle. Such a rotation can be random and transient 42 or unidirectional and sustained, i.e.…”

“…Are the consequences similar to the case of one obstacle being put in a bath of spherical ABPs? 41 Will the obstacle stimulate the aggregation of APs and will the APs orbit the obstacle collectively and form a sustained vortex? To answer these questions, we study, using two-dimensional simulations, a simple system composed of one circular obstacle and a bunch of APs.…”