Aspect-ratio-dependent void formation in active rhomboidal and elliptical particle systems

TL;DR

This study uses numerical simulations to explore how particle shape and aspect ratio influence void formation and size in active nematic systems with rhomboidal and elliptical particles, revealing shape-dependent differences in void characteristics.

Contribution

It provides new insights into how particle aspect ratio and shape affect void formation and size in active nematic systems, highlighting differences between rhomboidal and elliptical particles.

Findings

Void regions appear at high aspect ratios in both systems.

Void size increases with aspect ratio for rhomboidal particles.

Distribution of void sizes is broad for elliptical particles.

Abstract

We execute a numerical simulation on active nematics with particles interacting by an excluded volume effect. The systems with rhomboidal particles and that with elliptical particles are considered in order to investigate the effect of the direct contact of particles. In our simulation, the void regions, where the local number density is almost zero, appear in both systems when the aspect ratio of the particles is high. We focused on the relationship between the void regions and the particle orientation of the bulk. The particle number density, particle orientation, topological defects, and void regions are analyzed for different aspect ratios in both systems. The systems with rhomboidal particles have characteristic void sizes, which increase with an increase in the aspect ratio. In contrast, the distribution of the void-region size in the systems with elliptical particles is broad. The present results suggest that the void size in the systems with rhomboidal particles is determined by the correlation length of the particle orientational field around the void regions, while that might be determined by the system size in the systems with elliptical particles.