Abstract

In this talk, I will describe our recent and ongoing simulation efforts of hydrodynamic stabilisation of coherent structures formed by out of equilibrium spherical (colloidal) particles suspended in a fluid. I will provide examples of both internally and externally driven systems. In the first case we will consider active (self-propelling)particles, while in the second case a system of driven colloidal spinners is created by energising passive particles by an external rotational drive. In both of these systems, there exists an unexpected coupling between translational and rotational motion: Spherical active particles, modelled as squirmers, can form small hydrodynamically bound chiral spinners consisting of two or three particles, when exposed to gravity-like aligning field near a surface. Passive but rotationally driven particles show a spontaneous formation of a large scale vortex at low but finite Reynolds numbers. Finally, I will discuss mixtures of the driven spinners, where the other component can be either passive particles or particles with an opposite spin giving a rise to a racemic mixture.