Interfacial deformation and jetting of a magnetic fluid

Document Type

Article

Publication Date

1-2-2016

Abstract

An attractive technique for forming and collecting aggregates of magnetic material at a liquid-air interface by an applied magnetic field gradient was recently proposed, and its underlying principle was studied theoretically and experimentally (Tsai et al., 2013): when the magnetic field is weak, the deflection of the liquid-air interface has a steady shape, while for sufficiently strong fields, the interface destabilizes and forms a jet that extracts magnetic material. Motivated by this work, we develop a numerical model for the closely related problem of solving two-phase Navier-Stokes equations coupled with the static Maxwell equations. We computationally model the forces generated by a magnetic field gradient produced by a permanent magnet and so determine the interfacial deflection of a magnetic fluid (a pure ferrofluid system) and the transition into a jet. We analyze the shape of the liquid-air interface during the deformation stage and the critical magnet distance for which the static interface transitions into a jet. We draw conclusions on the ability of our numerical model to predict the large interfacial deformation and the consequent jetting, free of fitting parameters.

Identifier

84954125595 (Scopus)

Publication Title

Computers and Fluids

External Full Text Location

https://doi.org/10.1016/j.compfluid.2015.05.015

ISSN

00457930

First Page

149

Last Page

156

Volume

124

Grant

1211713

Fund Ref

National Science Foundation

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