Orientation dynamics of anisotropic particles in viscoelastic fluids

Abstract

The present work concerns the orientation dynamics of anisotropic particles in viscoelastic °uids. A spheroidal geometry is taken as being representative of an anisotropic, axisymmetric particle, and the work is an analytical investigation of the e®ects of weak inertia and viscoelasticity on the orientation of a spheroidal particle (both prolate and oblate) of an arbitrary aspect ratio in two canonical °ow situations: 1. A spheroid sedimenting in a quiescent °uid, and 2. A neutrally buoyant spheroid in a simple shear °ow Applications include sedimentation of muds and slurries, processing of cellulose ¯ber suspensions in the paper and pulp industry, and processing of ¯lled poly- meric materials (wherein anisotropic clay particles are typically used as cheap ¯ller materials).