Rotary oscillations of a micropolar fluid sphere in a bounded medium

Abstract

The present study examines the axisymmetric rotary oscillation of a micropolar fluid sphere in concentric spherical cavity filled with Newtonian viscous fluid. A continuity of velocity components and stress together with the spin vorticity relation are used at the interface between fluid-fluid regions. The torque exerted on the micropolar fluid sphere is obtained analytically and the real and imaginary torque coefficients are presented graphically. The effect of the micropolarity parameter, viscosity ratio and spin parameter on the torque are studied numerically. In the limiting cases, the torque acting on the rotating micropolar fluid sphere and solid sphere in concentric spherical cavity are obtained from the present analysis.