Low-Reynolds-number, bi-flagellated Quincke swimmers with multiple forms of motion

TL;DR

This paper demonstrates how bi-flagellated spheres can be propelled at low Reynolds number using static electric fields to induce Quincke rotation, revealing multiple motion modes and potential control methods for artificial swimmers.

Contribution

It introduces a novel electric field-driven propulsion mechanism for bi-flagellated swimmers, including multiple motion states and insights into their control.

Findings

Three distinct motion modes observed, including self-oscillatory behavior.

Electric fields can effectively induce and control swimmer locomotion.

Numerical simulations align with experimental results, confirming the propulsion mechanism.

Abstract

In the limit of zero Reynolds number (Re), swimmers propel themselves exploiting a series of non-reciprocal body motions. For an artificial swimmer, a proper selection of the power source is required to drive its motion, in cooperation with its geometric and mechanical properties. Although various external fields (magnetic, acoustic, optical, etc.) have been introduced, electric fields are rarely utilized to actuate such swimmers experimentally in unbounded space. Here we use uniform and static electric fields to demonstrate locomotion of a bi-flagellated sphere at low Re via Quincke rotation. These Quincke swimmers exhibit three different forms of motion, including a self-oscillatory state due to elasto-electro-hydrodynamic interactions. Each form of motion follows a distinct trajectory in space. Our experiments and numerical results demonstrate a new method to generate, and potentially control, the locomotion of artificial flagellated swimmers.