Dynamics of a magnetic particle in an oscillating magnetic field subject to a shear flow

Misra, I and Kumaran, V (2024) Dynamics of a magnetic particle in an oscillating magnetic field subject to a shear flow. In: Journal of Fluid Mechanics, 988 .

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Abstract

The orientational dynamics of a spherical magnetic particle in linear shear flow subjected to an oscillating magnetic field in the flow plane is analysed in the viscous limit. The shear is in the - plane, the magnetic field is in the direction and the vorticity is perpendicular to the flow in the direction. The relevant dimensionless groups are, the ratio of the frequency of the magnetic field and the strain rate, and, the ratio of the magnetic and hydrodynamic torques. As is decreased, there is a transition from in-plane rotation, where the rotation is in the flow (-) plane, to out-of-plane rotation, where the orientation vector is not necessarily in the - plane and the dynamics depends on the initial orientation. The particle rotation is phase-locked for in-plane rotation with discrete odd rotation number (number of rotations in one period of magnetic field oscillation), while the orbits are quasi-periodic with non-integer rotation number for out-of-plane rotation. For, regions of odd rotation number are bound by the lines and, and there are discontinuous changes in the rotation number and mean and root-mean-square torque at these lines. For, the domains of in-plane rotation of finite width in the - plane extend into downward cusps at. The orbits are quasi-periodic between these domains, where the rotation is out of plane. © The Author(s), 2024. Published by Cambridge University Press.

Item Type:	Journal Article
Publication:	Journal of Fluid Mechanics
Publisher:	Cambridge University Press
Additional Information:	The copyright for this article belongs to the publisher.
Keywords:	Magnetic domains; Magnetic fields; Oscillating flow; Viscous flow, Inplane rotation; Linear shear flow; Magnetic particle; Orientational dynamics; Oscillating magnetic fields; Out-of-plane rotation; Quasi-periodic; Rotation number; Viscous limits, Shear flow, hydrodynamics; magnetic field; shear flow; strain rate; torque; vorticity
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	13 Sep 2024 05:14
Last Modified:	13 Sep 2024 05:14
URI:	http://eprints.iisc.ac.in/id/eprint/86079

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