Abstract

We use fully-coupled three-dimensional computer simulations to examine the hydrodynamics of an elastic swimmer that swims in a viscous Newtonian fluid, and to probe how elasticity and resonance oscillations can be harnessed for efficient locomotion in a low-Reynolds-number environment. Our simulation approach is based on the lattice Boltzmann method. The swimmer is modeled as a rectangular elastic plate. We examine two types of swimmer actuation. In the first case, the elastic swimmer is actuated by imposing sinusoidal oscillations at its root. We also examine internally actuated swimmers that are driven by time varying internal moment producing swimmer bending. We probe the hydrodynamic forces and fluid structures generated by the swimmers and compare different actuation regimes. In particular, we show that the resonance actuation leads by the fastest swimmer propulsion velocity. This fast swimming, however, is inefficient, whereas an efficient swimming can be obtained for o ff-resonance frequencies. Furthermore, we compare our simulations of internally actuated swimmers with the experimental results for swimmers made of piezoelectric macro-fiber composites. The results are useful for designing efficient self-propelling fish-like robots driven by internally powered fins