Creeping flow around particles in a Bingham fluid

We revisit the variational setting of the creeping flow of Bingham fluid about a particle. We investigate two problems: the resistance and the mobility problem, which arise in the context of sedimentation. We present results and the general framework for uniqueness, symmetry and reversibility properties of solutions, and clarify the relation between resistance and mobility problems. We also consider general properties of the static stability limit (or load limit). In the second part of the paper we apply insights gained from the first part to the computation of 2D exterior flow around an infinite cylinder with elliptical cross-section. We study the static stability limit and find that the limiting flow solution approaches the perfectly plastic solid solution.