Particle rotation and translation in a fluid with spin

The effects of fluid spin (internal angular momentum of the fluid molecules) are examined for test particle rotation and translation. Two mechanisms of spin change, namely coupling to linear velocity and spin diffusion, are included in the full hydrodynamic description. The associated general boundary conditions are determined as linear constitutive relations on the test particle surface. Numerical calculations of rotational and translational friction are presented as functions of frequency, boundary conditions and fluid density. In addition, the deGroot-Mazur approximation which neglects spin diffusion is examined. The relevance of these results for time correlation function calculations is discussed.