Hydrodynamic scattering of a neutral squirmer by a near-wall curved obstacle: MPCD simulations and analytical theory.

Abstract

Microscopic swimming organisms exhibit a wide range of behaviours, including swarming, synchronized motion, and clustering, driven by hydrodynamic interactions with each other and the environment. Designing artificial microswimmers requires understanding the flow in constrained environments, such as microchannels or between obstacles. In this article, we explore the dynamics of a circular neutral squirmer near a curved wall-mounted obstacle. Using a multiparticle collision dynamics simulation, it is observed that the neutral squirmer always scatters from the obstacle. We measured the scattering angle from simulation, which agrees with analytical calculations based on Faxén's law and the far-field approximation. Further investigation reveals similarities to classical scattering with a repulsive potential.