scholarly journals Experimental and numerical study of rotating magnetic field driven flow in cylindrical enclosures with different aspect ratios

2004 ◽  
Vol 40 (2) ◽  
pp. 147-160 ◽  
Keyword(s):  
Magnetic Field ◽  
Numerical Study ◽  
Rotating Magnetic Field ◽  
Aspect Ratios

A numerical study of flows driven by a rotating magnetic field in a square container

PAMM ◽  
2008 ◽  
Vol 8 (1) ◽  
pp. 10953-10954 ◽  
Author(s):  
K. Fraňa ◽  
J. Stiller ◽  
K. Horáková
Keyword(s):  
Magnetic Field ◽  
Numerical Study ◽  
Rotating Magnetic Field

scholarly journals 3D motion of flexible ferromagnetic filaments under a rotating magnetic field

Soft Matter ◽  
2020 ◽  
Vol 16 (18) ◽  
pp. 4477-4483 ◽  
Author(s):  
Abdelqader Zaben ◽  
Guntars Kitenbergs ◽  
Andrejs Cēbers
Keyword(s):  
Magnetic Field ◽  
Numerical Study ◽  
Rotating Magnetic Field ◽  
3D Motion ◽  
Rotating Field

Experimental and numerical study of flexible ferromagnetic filaments reveal different regimes, when subjected to a 2D rotating field. The filaments were found to have a 3D motion at higher frequencies.

Inertial wave dynamics in a rotating liquid metal

2014 ◽  
Vol 753 ◽  
pp. 472-498 ◽  
Author(s):  
Tobias Vogt ◽  
Dirk Räbiger ◽  
Sven Eckert
Keyword(s):  
Magnetic Field ◽  
Liquid Metal ◽  
Swirling Flow ◽  
Harmonic Wave ◽  
Wave Mode ◽  
Rotating Magnetic Field ◽  
Inertial Waves ◽  
Aspect Ratios ◽  
Inertial Wave ◽  
Wave Modes

AbstractThe dynamics of free and forced inertial waves inside cylinders of different aspect ratios ($\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}A=H_0/2R_0$) were investigated experimentally in this study. The liquid metal GaInSn was chosen as the fluid in order to enable a contactless stimulation of the flow by means of alternating electromagnetic fields. A rotating magnetic field generates the rotating motion of the liquid, whereas periodic modulations of the field strength and short pulses excite specific wave modes. Ultrasound Doppler velocimetry was used to record the flow structure and to identify inertial waves in the set-up. Our experiments demonstrate selective excitation of different inertial wave modes by deliberate variation of the magnetic field parameters. Furthermore, it was found that turbulent perturbations in the boundary layers of the swirling flow are able to induce an inertial wave mode that survives over a long time. Experiments at the fundamental resonance have shown that multiple harmonic wave modes appeared simultaneously. The measured inertial wave frequencies were compared to the predictions of the linear inviscid theory.

Torque and Bulk Flow of Ferrofluid in an Annular Gap Subjected to a Rotating Magnetic Field

2006 ◽  
Vol 129 (4) ◽  
pp. 412-422 ◽  
Author(s):  
Arlex Chaves ◽  
Fernando Gutman ◽  
Carlos Rinaldi
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Axial Velocity ◽  
Field Amplitude ◽  
Bulk Flow ◽  
Rotating Magnetic Field ◽  
Flow Measurements ◽  
Aspect Ratios ◽  
Cylindrical Annulus ◽  
Annular Gap

We report analysis and measurements of the torque and flow of a ferrofluid in a cylindrical annulus subjected to a rotating magnetic field perpendicular to the cylinder axis. The presence of the inner cylinder results in a nonuniform magnetic field in the annulus. An asymptotic analysis of the ferrohydrodynamic torque and flow assuming linear magnetization and neglecting the effect of couple stresses indicated that the torque should have a linear dependence on field frequency and quadratic dependence on field amplitude. To the order of approximation of the analysis, no bulk flow is expected in the annular gap between stationary cylinders. Experiments measured the torque required to restrain a polycarbonate spindle surrounded by ferrofluid in a cylindrical container and subjected to the rotating magnetic field generated by a two-pole magnetic induction motor stator, as a function of the applied field amplitude and frequency, and for various values of the geometric aspect ratios of the problem. The ultrasound velocity profile method was used to measure the azimuthal and axial velocity profiles in the ferrofluid contained in the annular gap of the apparatus. Flow measurements show the existence of a bulk azimuthal ferrofluid flow between stationary coaxial cylinders with a negligible axial velocity component. The fluid was found to corotate with the applied magnetic field. Both the torque and flow measurements showed power-of-one dependence on frequency and amplitude of the applied magnetic field. This analysis and these experiments indicate that the action of antisymmetric stresses is responsible for the torque measured on the inner cylinder, whereas the effect of body couples is likely responsible for bulk motion of the ferrofluid.

scholarly journals Effect of thermally active zones and direction of magnetic field on hydromagnetic convection in an enclosure

2011 ◽  
Vol 15 (suppl. 2) ◽  
pp. 367-382 ◽  
Author(s):  
Sivanandam Sivasankaran ◽  
Marimuthu Bhuvaneswari
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Average Nusselt Number ◽  
Hartmann Number ◽  
Numerical Study ◽  
Governing Equations ◽  
Aspect Ratios ◽  
Active Zones ◽  
Volume Method ◽  
The Magnetic Field

The aim of the present numerical study is to investigate the effect of thermally active zones and direction of the external magnetic field on hydromagnetic convection in an enclosure. Nine different relative positions of the thermally active zones are considered. Top and bottom of the enclosure are adiabatic. The governing equations are solved by the finite volume method. The results are obtained for different directions of the external magnetic field, thermally active locations, Hartmann numbers, Grashof numbers and aspect ratios. It is observed that the heat transfer is enhanced for heating location is either at middle or at bottom of the hot wall while the cooling location is either at top or at middle of the cold wall. The flow field is altered when changing the direction of the magnetic field in the presence of strong magnetic field. The average Nusselt number decreases with an increase of the Hartmann number and increases with increase of the Grashof number and aspect ratio.

Global Modeling of Directional Solidification of Aluminum Alloys Using the Software Package CrysVUn

2006 ◽  
Vol 508 ◽  
pp. 437-442 ◽  
Author(s):  
Johannes Dagner ◽  
A. Weiß ◽  
Marc Hainke ◽  
Gerhard Zimmermann ◽  
Georg Müller
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Model ◽  
Directional Solidification ◽  
Software Package ◽  
Numerical Study ◽  
Rotating Magnetic Field ◽  
Convective Conditions ◽  
Global Modeling

A global numerical model of a Bridgman furnace is developed and validated. The model includes heat transfer due to radiation and conduction in a stationary setup. The rotating magnetic field (RMF) device mounted on the facility is implemented into the model also. A numerical study on the flow field caused by the axial non-uniform RMF and natural convection is performed, helping to get a better understanding of the convective conditions during the directional solidification experiments.

Particle Actuation by Rotating Magnetic Fields in Microchannels: A Numerical Study

Soft Matter ◽  
2021 ◽  
Author(s):  
Seokgyun Ham ◽  
Wen-Zhen Fang ◽  
Rui Qiao
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Particles ◽  
Numerical Study ◽  
Rotating Magnetic Field ◽  
Rotating Magnetic Fields ◽  
Translation Motion

Magnetic particles confined in microchannels can be actuated to perform translation motion using a rotating magnetic field, but their actuation in such a situation is not yet well understood. Here,...

Experimental and numerical study of Rayleigh-Bénard convection affected by a rotating magnetic field

1999 ◽  
Vol 11 (4) ◽  
pp. 853-861 ◽  
Author(s):  
J. Friedrich ◽  
Y.-S. Lee ◽  
B. Fischer ◽  
C. Kupfer ◽  
D. Vizman ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Numerical Study ◽  
Rotating Magnetic Field ◽  
Bénard Convection ◽  
Benard Convection ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard
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