Motion of a ferrosuspension in rotating magnetic fields

O. A. Glazov

Abstract
The possibility of inducing rotational motion of a ferrosuspension by a magnetic field traveling in an azimuthal direction is investigated. A hydrodynamic model which takes into accourit the rotation of the suspended particles is used to describe the motion of the suspension. The peak value and profile of the azimuthal velocity are determined in the limiting cases of weak and strong magnetic fields. In weak magnetic fields the azimuthal velocity is much smaller than the phase velocity of the traveling magnetic field. In strong fields the limiting velocity is independent of the magnetic field. For sufficiently large volume concentration and harmonic number of the traveling field the velocity becomes comparable with the phase velocity of the traveling magnetic field. The rotation of polarizable fluids by a rotating uniform magnetic field is attributed to the presence of higher spatial harmonics. Magnetic fields with the number of the fundamental harmonic greater than unity are recommended for induction of rotation of a ferrosuspension. In this case the induction of rotation will be determined by the fundamental harmonic, and not the higher harmonics, with the result that much greater velocities of rotation can be attained.