二重円管内の磁性流体の外部磁場に対する磁気的応答

抄録

A phenomenological treatment is given for the steady ferrofluid flows in annular pipes in the presence of uniform external magnetic fields. It is found that the apparent viscosity of a dilute colloidal suspension of ferromagnetic particles is a marked function of both the magnitude and direction of an externally applied magnetic field. The experimental fact shown by McTague (1969) that the additional viscosity is greater by a factor of 2 for the field parallel to the flow than with it perpendicular is theoretically explained. Analytical expressions of the distributions of velocity and angular velocity of the ferrofluid in annular pipes are derived under the influence of the external field. The induced magnetization calculated here to first order is skewsymmetric with respect to the plane through the center line of the pipe and perpendicular to the applied magnetic field.