Title

Width of a Ferrofluid Finger: Hysteresis and a Double Energy Minimum

Roles

Student author: Narelle J. Hillier

Document Type

Article

Publication Date

3-2007

Department

Physics

Language

English

Publication Title

Physical Review E

Abstract

We study a ferrofluid in a horizontal Hele-Shaw geometry subjected to a vertical magnetic field. Specifically, we calculate the energy of a single ferrofluid finger using an idealized model for the finger. By minimizing this energy, we find the preferred finger width as a function of the applied field. Our model predicts a first order transition as the fluid abruptly transforms from a circular drop to a finite finger. This behavior arises because of a double energy minimum that yields two different stable configurations for the system. Interestingly, this system exhibits hysteresis as the circle-to-finger (increasing field) transition occurs at a different applied field than the finger-to-circle (decreasing field) transition. We carry out a simple experiment and observe good overall agreement with the theoretical predictions.

Comments

For more information on the published version, visit American Physical Society's (APS) Website.

DOI

10.1103/PhysRevE.75.036314

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