SUMMARY

Fish swimming is characterized by astonishing versatility: from fast burst and sharp turns to fast and efficient cruising. By adjusting their flexible body and tail through muscle activation, fish are capable of harnessing various changing flow conditions. Motivated by this adaptability, researchers and engineers have striven to apply the same principles to their robotic fish designs. In this work, we numerically investigate the problem of bio-mimetic locomotion using a fully-coupled three-dimensional fluid-structure interaction computational framework. The bio-inspired propulsor is modeled as a thin elastic plate oscillating in a Newtonian fluid. We systematically explore the impact of several design parameters on the propulsor swimming performance, including the effects of non-uniform properties, flow regime, aspect and mass ratios as well as the actuation mechanism itself. We find that the driving mechanism and frequency of the elastic swimmer is a key design parameter. When comparing conventional heaving and more recent muscle-like actuation, we find critical differences in bending patterns. These critical differences in bending patterns in turn are associated to an improved performance of conventional heaving over muscle-like actuation. Although conventional heaving is found to outperform muscle-like actuation, we find that the swimming performance can be further enhanced by combining novel and conventional. Additionally, we show that tapered swimmers display particularly advantageous features over a wide range of driving frequencies. https://bluejeans.com/757709823