Understanding the effect of tapering geometry on swimming performance of biomimetic elastic propulsors

Thickness tapering leads to enhanced hydrodynamic performance of oscillating elastic propulsors by drastically increasing the hydrodynamic thrust and efficiency compared to elastic propulsors with uniform thickness. Thickness tapering modifies the bending pattern by minimizing the wave reflection at the propulsor training edge, which in turn promotes the development of the traveling waves propagating along the propulsor length. We use fluid-structure interaction computational modeling to explore the hydrodynamic mechanism leading to enhanced hydrodynamics of tapered propulsors. In particular, we probe the effects of the tapering length and Reynolds number on the emerging flow patterns and hydrodynamic forces. Our simulations provide useful guidelines for designing efficient bio-mimetic robotic swimmers.