Micro-swimmers with hydrodynamic interactions

The low-Reynolds-number motions of Purcell’s three-link swimmer, and of a closely related two-paddle swimmer, are investigated and compared using slender-body theory and resistive-force theory. The results are compared (in the case of the three-link swimmer) with the resistive-force calculations of Becker, Koehler and Stone (BKS). In particular, we examine the effect of hydrodynamic interaction and slenderness on the displacement and efficiency of the swimmers. The BKS analysis is, for the most part, confirmed and extended. However, deviations of up to 43% are found in cases where the swimmer propels itself with large stroke angles. Finally, we discuss recent experimental data in light of our numerical results.