Flows and Instabilities of Ferrofluids at the Microscale

TL;DR

This study explores the complex flow behaviors and instabilities of ferrofluid microdrops under magnetic fields, revealing new patterns and configurations relevant for microfluidic applications.

Contribution

It uncovers previously unobserved instability and flow patterns of ferrofluid microdrops subjected to magnetic fields, expanding understanding of microscale ferrofluid dynamics.

Findings

Discovery of new instability and flow patterns in ferrofluid microdrops.

Identification of various microdrop configurations such as star-like, spiral, and ring shapes.

Insights into magnetic field effects on microdrop deformation and behavior.

Abstract

In the present work we report on the behavior of ferrofluid microdrops in an immiscible nonmagnetic carrier fluid and vice versa subjected to the action of magnetic fields. Our experiments evidence previously unexplored instability and flow patterns. We investigated the instabilities initiated by constant magnetic field and by combined action of constant and rotating magnetic fields. The observed instabilities lead to the formation of various microdrop configurations such as star-like and comb-like shapes, bending deformation, ridges and crests, spiral arms and rings, etc. The reviled peculiarities of the microscopic drops behavior can be of interest in applications to the ferrofluid-based microfluidics.