Impact of wall constraint on the dynamics of self-propelled particles*

The presence of wall constraint strongly affects the motions of dispersed particles in a fluid. A striking example can be seen in the dynamics of self-propelled particles near fluid/solid boundaries where the single (collective) motion of such particle(s) depend sensitively on the detailed flow profile around them. In the present study, we investigate the dynamics of two popular types of self-propelled particles, i.e., spherical micro-swimmers (squirmers) and rolling spheres (Quincke rollers) on a flat plate and by means of direct numerical simulation of fluid/particle composite systems with fully resolving the hydrodynamics.