Understanding the effect of thickness tapering on swimming performance of 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 leads to the acoustic black hole effect at the propulsor trailing edge that minimizes the wave reflection and 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 the enhanced hydrodynamics of tapered propulsors. In particular, we probe the effects of the tapering geometry and the propulsor aspect ratio on the emerging flow patterns and hydrodynamic forces. Our simulations provide useful guidelines for designing efficient bio-mimetic robotic swimmers.