Hydrodynamic attraction and repulsion between asymmetric rotors

TL;DR

This paper investigates how asymmetric rotors interact hydrodynamically at low Reynolds numbers, revealing conditions for attraction or repulsion that depend on shape and external field coupling, with implications for particle manipulation.

Contribution

It introduces a numerical analysis of asymmetric rotor interactions under rotating fields, highlighting shape-dependent conformational changes and symmetry breaking effects.

Findings

Dissimilar asymmetric shapes lead to conformational rearrangements.

Rotating fields can induce either attraction or repulsion between rotors.

Potential applications in particle assembly and micro-swimmer studies.

Abstract

At low Reynolds numbers, the hydrodynamic interaction between dumbbells driven by an external rotating field can be attractive or repulsive. Dumbbells of dissimilar asymmetric shape or different coupling to the external field undergo conformational rearrangements that break the time reversal symmetry. The parameter ranges leading to attraction or repulsion are explored numerically. The results of our simulations suggest that rotating fields may be a useful avenue for the assembly, disassembly, and sorting of particles of different shape as well as for the study of collective micro-swimmers.