VISCOSITY OF MAGNETIC FLUID IN A MAGNETIC FIELD

Fluids with ferromagnetic properties may be formed by a colloidal suspension of solid magnetic particles such as magnetite in a parent liquid. The viscosity of the fluid in a magnetic field is predicted by dimensional analysis to be a function of the ratio of hydrodynamic stress to magnetic stress, γν0 MH. The prediction is verified experimentally and from the correlated data it is determined that for values of this ratie greater than 10-4 there is no change of viscosity in an applied field. For values between 10-6 and 10-4 the viscosity is a function of both magnetic field and rate of shear. Theoretically, for high values of applied field, the viscosity again becomes independent of field or shear rate. © 1969.