Magnetic fluid behavior in uniform DC, AC, and rotating magnetic fields

Scott Rhodes; Xiaowei He; Shihab Elborai; Se Hee Lee; Markus Zahn

doi:10.1016/j.elstat.2005.10.021

Magnetic fluid behavior in uniform DC, AC, and rotating magnetic fields

Scott Rhodes, Xiaowei He, Shihab Elborai, Se Hee Lee, Markus Zahn

Department of Electrical Engineering

Department of Electrical Engineering and Computer Science

Research output: Contribution to journal › Article › peer-review

27 Scopus citations

Abstract

New flows and instabilities are demonstrated for magnetic fluids and by dual analogy to dielectric fluids. If a fluid drop is contained in a thin gap between two glass plates (Hele-Shaw cell) with a simultaneously applied in-plane rotating field and a DC axial field, smooth spirals or an abrupt transformation to many small droplets can occur. A preliminary minimum magnetization and surface energy analysis is presented to model the abrupt transformation in ferrofluids. An analysis of effective DC magnetoviscosity is also presented for planar Couette flow with an applied uniform DC field transverse to a duct axis with the effective magnetoviscosity and flow spin velocity calculated as a function of field strength. Related Couette viscometer measurements of ferrofluid viscosity show zero and negative magnetoviscosity values for rotating magnetic fields.

Original language	English
Pages (from-to)	513-519
Number of pages	7
Journal	Journal of Electrostatics
Volume	64
Issue number	7-9
DOIs	https://doi.org/10.1016/j.elstat.2005.10.021
State	Published - Jul 2006

Keywords

Ferrofluids
Ferrohydrodynamics
Magnetic Bond number
Magnetic fluids
Magnetic torque
Magnetoviscosity
Negative viscosity

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10.1016/j.elstat.2005.10.021

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title = "Magnetic fluid behavior in uniform DC, AC, and rotating magnetic fields",

abstract = "New flows and instabilities are demonstrated for magnetic fluids and by dual analogy to dielectric fluids. If a fluid drop is contained in a thin gap between two glass plates (Hele-Shaw cell) with a simultaneously applied in-plane rotating field and a DC axial field, smooth spirals or an abrupt transformation to many small droplets can occur. A preliminary minimum magnetization and surface energy analysis is presented to model the abrupt transformation in ferrofluids. An analysis of effective DC magnetoviscosity is also presented for planar Couette flow with an applied uniform DC field transverse to a duct axis with the effective magnetoviscosity and flow spin velocity calculated as a function of field strength. Related Couette viscometer measurements of ferrofluid viscosity show zero and negative magnetoviscosity values for rotating magnetic fields.",

keywords = "Ferrofluids, Ferrohydrodynamics, Magnetic Bond number, Magnetic fluids, Magnetic torque, Magnetoviscosity, Negative viscosity",

author = "Scott Rhodes and Xiaowei He and Shihab Elborai and Lee, {Se Hee} and Markus Zahn",

year = "2006",

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doi = "10.1016/j.elstat.2005.10.021",

language = "English",

volume = "64",

pages = "513--519",

journal = "Journal of Electrostatics",

issn = "0304-3886",

publisher = "Elsevier B.V.",

number = "7-9",

}

TY - JOUR

T1 - Magnetic fluid behavior in uniform DC, AC, and rotating magnetic fields

AU - Rhodes, Scott

AU - He, Xiaowei

AU - Elborai, Shihab

AU - Lee, Se Hee

AU - Zahn, Markus

PY - 2006/7

Y1 - 2006/7

N2 - New flows and instabilities are demonstrated for magnetic fluids and by dual analogy to dielectric fluids. If a fluid drop is contained in a thin gap between two glass plates (Hele-Shaw cell) with a simultaneously applied in-plane rotating field and a DC axial field, smooth spirals or an abrupt transformation to many small droplets can occur. A preliminary minimum magnetization and surface energy analysis is presented to model the abrupt transformation in ferrofluids. An analysis of effective DC magnetoviscosity is also presented for planar Couette flow with an applied uniform DC field transverse to a duct axis with the effective magnetoviscosity and flow spin velocity calculated as a function of field strength. Related Couette viscometer measurements of ferrofluid viscosity show zero and negative magnetoviscosity values for rotating magnetic fields.

AB - New flows and instabilities are demonstrated for magnetic fluids and by dual analogy to dielectric fluids. If a fluid drop is contained in a thin gap between two glass plates (Hele-Shaw cell) with a simultaneously applied in-plane rotating field and a DC axial field, smooth spirals or an abrupt transformation to many small droplets can occur. A preliminary minimum magnetization and surface energy analysis is presented to model the abrupt transformation in ferrofluids. An analysis of effective DC magnetoviscosity is also presented for planar Couette flow with an applied uniform DC field transverse to a duct axis with the effective magnetoviscosity and flow spin velocity calculated as a function of field strength. Related Couette viscometer measurements of ferrofluid viscosity show zero and negative magnetoviscosity values for rotating magnetic fields.

KW - Ferrofluids

KW - Ferrohydrodynamics

KW - Magnetic Bond number

KW - Magnetic fluids

KW - Magnetic torque

KW - Magnetoviscosity

KW - Negative viscosity

UR - http://www.scopus.com/inward/record.url?scp=33646773910&partnerID=8YFLogxK

U2 - 10.1016/j.elstat.2005.10.021

DO - 10.1016/j.elstat.2005.10.021

M3 - Article

AN - SCOPUS:33646773910

SN - 0304-3886

VL - 64

SP - 513

EP - 519

JO - Journal of Electrostatics

JF - Journal of Electrostatics

IS - 7-9

ER -

Magnetic fluid behavior in uniform DC, AC, and rotating magnetic fields

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Keywords

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