Tangential stresses on the magnetic fluid boundary and rotational effect

A. F. Pshenichnikov - A. V. Lebedev

Institute of Continuous Media Mechanics, UB of the Russian Academy of Sciences, 1 Korolyov St., 614013 Perm, Russia

Abstract
The tangential magnetic stresses at the boundary of magnetic fluid placed in a rotating magnetic field have been investigated. These stresses proved out to be the main reason of the rotational effect in the region of weak magnetic fields. The non-monotonic dependence of the torques on the magnetic phase concentration has been revealed. The calculation of the torques carried out on the basis of the Shliomis stress tensor is in perfect agreement with the experimental data. The calculated values of the velocity of the hydrodynamic flow differ by 15-–20 percents from the experimental values. This discrepancy is explained by non-Newtonian behaviour of the concentrated magnetic fluid. Figs 5, Refs 14.