Purcell's swimmer in a shear-thinning fluid

Abstract

We utilize Purcell's swimmer as a model swimmer to probe the impacts of shear-thinning rheology, an ubiquitous non-Newtonian behavior of biological fluids, on swimming at low Reynolds numbers. We show how the propulsion characteristics of Purcell's swimmer in a shear-thinning fluid differ from that in a Newtonian fluid in terms of both magnitude and direction of propulsion velocity. We also demonstrate how unequal arm rotational rates can couple with the shear-thinning effect to induce net vertical motion of the swimmer otherwise impossible in a Newtonian fluid.