Torque characteristics of Spherical Couette flow of a magnetic fluid

Spherical Couette flow is the flow in the gap between two concentric spheres. Torque, the measure of the shearing stresses acting on a sphere, is one of the important parameters of flow, particularly in the case of a narrow gap. The purpose of the present study is to investigate flow by determining the transitional characteristics of the torque generated by a flow field in various regines. The flow of a magnetic fluid is analyzed within the narrow spherical gap that arises in the rotation of an inner sphere with various rotational Reynolds numbers. The magnetic fluid is treated as a continuum, and the equations of ferrohydrodynamics, in conjunction with the internal degrees of particle freedom, are solved numerically using the method of finite differences. The total stress acting in the surface of the inner sphere is calculated using the stress tensor after completion of the flow-field calculation. The present study involves research into the characteristics of the torque in three types of advancement, with the result compared to data for phenomenological modeling of the flow field. 9 refs., 5 figs