Stokesian swimmers and active particles

TL;DR

This paper analyzes the steady state flow patterns of distorting spheres in low Reynolds number environments, emphasizing the importance of accurate flow modeling for understanding active particle interactions.

Contribution

It introduces a bilinear theory approach to study flow patterns of active particles, highlighting the significance of phase in hydrodynamic interactions.

Findings

Steady flow patterns depend on sphere distortion and phase.

Flow patterns are not always indicative of swimming motion.

Phase plays a crucial role in hydrodynamic interactions.

Abstract

The net steady state flow pattern of a distorting sphere is studied in the framework of the bilinear theory of swimming at low Reynolds number. It is argued that the starting point of a theory of interacting active particles should be based on such a calculation, since any arbitrarily chosen steady state flow pattern is not necessarily the result of a swimming motion. Furthermore, it is stressed that as a rule the phase of stroke is relevant in hydrodynamic interactions, so that the net flow pattern must be used with caution.