Long-range interactions and phase defects in chains of fluid-coupled oscillators

TL;DR

This study investigates how long-range hydrodynamic interactions influence collective dynamics and phase defects in chains of fluid-coupled oscillators, revealing transitions from wave-like patterns to chevrons and chimera-like states.

Contribution

It introduces a minimal experimental and numerical model showing the impact of interaction range on collective oscillation patterns and phase-locking in fluid-coupled systems.

Findings

Transition from traveling wave to chevron pattern with increased distance from the wall

Observation of periodic phase defects and chimera-like states

Hydrodynamic interaction range critically affects collective dynamics

Abstract

Eukaryotic cilia and flagella are chemo-mechanical oscillators capable of generating long-range coordinated motions known as metachronal waves. Pair synchronization is a fundamental requirement for these collective dynamics, but it is generally not sufficient for collective phase-locking, chiefly due to the effect of long-range interactions. Here we explore experimentally and numerically a minimal model for a ciliated surface; hydrodynamically coupled oscillators rotating above a no-slip plane. Increasing their distance from the wall profoundly effects the global dynamics, due to variations in hydrodynamic interaction range. The array undergoes a transition from a traveling wave to either a steady chevron pattern or one punctuated by periodic phase defects. Within the transition between these regimes the system displays behavior reminiscent of chimera states.