Three-sphere swimmer in a nonlinear viscoelastic medium.

Journal article

A simple model for a swimmer consisting of three colinearly linked spheres attached by rods and oscillating out of phase to break reciprocal motion is analyzed. With a prescribed forcing of the rods acting on the three spheres, the swimming dynamics are determined analytically in both a Newtonian Stokes fluid and a zero Reynolds number, nonlinear, Oldroyd-B viscoelastic fluid with Deborah numbers of order one (or less), highlighting the effects of viscoelasticity on the net displacement of swimmer. For instance, the model predicts that the three-sphere swimmer with a sinusoidal, but nonreciprocal, forcing cycle within an Oldroyd-B representation of a polymeric Boger fluid moves a greater distance with enhanced efficiency in comparison with its motility in a Newtonian fluid of the same viscosity. Furthermore, the nonlinear contributions to the viscoelastic constitutive relation, while dynamically nontrivial, are predicted a posteriori to have no effect on swimmer motility at leading order, given a prescribed forcing between spheres.

Authors: Curtis, M; Gaffney, E

• Journal: Physical review. E, Statistical, nonlinear, and soft matter physics
• Volume: 87
• Issue: 4
• Pages: 043006
• Publication date: 2013-04-01
• DOI: 10.1103/physreve.87.043006
• EISSN: 1550-2376
• ISSN: 1539-3755
• Language: English
• Keywords: Nonlinear Dynamics; Hydrodynamics; Viscoelastic Substances; Rheology; Motion