We report measurements of the torque required to restrain a polycarbonate spindle surrounded by ferrofluid in a cylindrical container and subjected to the rotating field generated by a two-pole magnetic induction motor stator, as a function of applied field amplitude and frequency, and for various values of the geometric aspect ratios of the problem. Simultaneously, an ultrasonic method was used to measure the azimuthal velocity profiles in the ferrofluid contained in the annular gap of our apparatus. These measurements are compared to a rigorous regular perturbation solution in the small parameter Ωτ (Ω = frequency and τ = ferrofluid magnetic relaxation time) of the ferrohydrodynamic flow problem in the zero spin viscosity and linear magnetization limits.

Volume Subject Area:
Fluids Engineering
Topics:
Containers, Engines, Ferrofluids, Flow (Dynamics), Magnetic induction, Magnetic relaxation, Magnetization, Motors, Nanoparticles, Poles (Building), Rotation, Stators, Torque, Viscosity
1.
Tsebers
 
A. O.
,
Interfacial stresses in the hydrodynamics of liquids with internal rotation
.
Magnitnaya Gidrodynamika
,
1975
.
11
(
1
): p.
79
–
82
.
2.
Rinaldi
 
C.
,
Gutman
 
F.
,
He
 
X.
,
Rosenthal
 
A. D.
, and
Zahn
 
M.
,
Magnetoviscosity and torque measurements on ferrofluid cylinder in rotating magnetic fields
.
Journal of Magnetism and Magnetic Materials
,
2005
.
289
: pp.
307
–
310
.
3.
Pshenichnikov
 
A. F.
and
Lebedev
 
A. V.
,
Tangential stresses on the magnetic fluid boundary and the rotational effect
.
Magnitnaya Gidrodynamika
,
2000
.
36
(
4
): p.
254
–
263
.
4.
Rosensweig
 
R. E.
,
Popplewell
 
J.
, and
Johnston
 
R. J.
,
Magnetic fluid motion in rotating field
.
Journal of Magnetism and Magnetic Materials
,
1990
.
85
: p.
171
–
180
.
5.
Takeda
 
Y.
,
Velocity profile measurement by ultrasonic Doppler method
.
Experimental Thermal and Fluid Science
,
1995
.
10
: p.
444
–
453
.
6.
Rosensweig, R.E., Ferrohydrodynamics. 1997, Mineola, NY: Dover Publications.
7.
Rosenthal
 
A. D.
,
Rinaldi
 
C.
, and
Zahn
 
M.
,
Torque Measurements in Spin-Up Flow of Ferrofluids
.
Journal of Fluids Engineering - ASME
,
2004
.
126
(
2
): p.
198
–
205
.
8.
Lehlooh
 
A. F.
,
Mahmood
 
S. H.
, and
Williams
 
J. M.
,
On the particle size dependence of the magnetic anisotropy energy constant
.
Physica B
,
2002
.
321
(
1–4
): p.
159
–
162
.
9.
Kikura
 
H.
,
Takeda
 
Y.
, and
Sawada
 
T.
,
Velocity profile measurements of magnetic fluid flow using ultrasonic Doppler method
.
Journal of Magnetism and Magnetic Materials
,
1999
.
201
: p.
276
–
280
.
10.
Sawada
 
T.
,
Nishiyama
 
H.
, and
Tabata
 
T.
,
Influence of a magnetic field on ultrasound propagation in a magnetic fluid
.
Journal of Magnetism and Magnetic Materials
,
2002
.
252
(
1–3
): p.
186
–
188
.
11.
Takeda
 
Y.
,
Ultrasonic Doppler method for velocity profile measurement in fluid dynamics and fluid engineering
.
Experiments in Fluids
,
1999
.
26
: p.
177
–
178
.
12.
de Gans
 
B. J.
,
Hoekstra
 
H.
, and
Mellema
 
J.
,
Non-linear magnetorheological behaviour of an inverse ferrofluid
.
Faraday Discussions
,
1999
(
112
): p.
209
–
224
.
13.
de Gans
 
B. J.
,
Blom
 
C.
,
Mellema
 
J.
, and
Philipse
 
A. P.
,
Preparation and magnetisation of a silica-magnetite inverse ferrofluid
.
Journal of Magnetism And Magnetic Materials
,
1999
.
201
: p.
11
–
13
.
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