  The results of an experimental investigation of a sphere performing torsional
oscillations in a Stokes flow are presented. A novel experimental set up was
developed which enabled the motion of the sphere to be remotely controlled
through application of an oscillatory magnetic field. The response of the
sphere to the applied field was characterised in terms of the viscous, magnetic
and gravitational torques acting on the sphere. A mathematical model of the
system was developed and good agreement was found between experimental and
theoretical results. The flow resulting from the motion of the sphere was
measured and the fluid velocity was found to have an inverse square dependence
on radial distance from the sphere. Agreement between measurements and the
analytical solution for the fluid velocity indicates that the flow may be
considered Stokesian.
