Magnetic fluid as a continuum with internal degrees of freedom

A closed system of equations governing thermomechanics of magnetic fluids is formulated with magnetization relaxation included. The material parameters are estimated. Approximate formulations of the dynamic megnetization equations are presented and the ranges of their validity are discussed. The dimensionless groups, which determine the magnetic fluid mechanics are introduced and their ranges are found. Particular effects due to the magnetization relaxation are considered.