Flow of a ferrofluid down a tube in an oscillating magnetic field - art. no. 021508

The magnetoviscosity of a ferrofluid flowing down a circular tube in the pr esence of a magnetic field oscillating in the direction of the axis is stud ied on the basis of ferrohydrodynamics, Maxwell's equations of magnetostati cs, and a relaxation equation for the magnetization. Three different relaxa tion equations, proposed in the literature, are considered. For large ampli tude of the oscillating field the three equations lead to different values of the magnetoviscosity. For large magnetic permeability the self-consisten t magnetic field generated by the magnetization has significant effect.