Hydrodynamics and Flow Characterization of Tuna-Inspired Propulsion in Forward Swimming

Abstract

A combined experimental and numerical approach is employed to study the hydrodynamic performance and characterize the flow features of thunniform swimming by using a tuna-inspired underwater vehicle in forward swimming. The three-dimensional, time-dependent kinematics of the body-fin system of the underwater vehicle is obtained via a stereo-videographic technique. A high-fidelity computational model is then directly reconstructed based on the experimental data. A sharp-interface immersed-boundary-method (IBM) based incompressible flow solver is employed to compute the flow. The primary objective of the computational effort is to quantify the thrust performance of the model. The body kinematics and hydrodynamic performances are quantified and the dynamics of the vortex wake are analyzed. Results have shown significant leading-edge vortex at the caudal fin and unique vortex ring structures in the wake. The results from this work help to bring insight into understanding the thrust producing mechanism of thunniform swimming and to provide potential suggestions in improving the hydrodynamic performance of swimming underwater vehicles.

Tunabot Flex: a tuna-inspired robot with body flexibility improves high-performance swimming

“…We explore the impact of body flexibility on high-performance fish swimming and compare our results against data for tunas and other fishes. This study is one of the first to compare COT curves of a robotic fish against its biological, species-specific counterpart, and we also compare Tunabot Flex against other fish robots including the previous generation Tunabot [60,75]. By doing so, we quantify progress towards fish-like, highperformance locomotion.…”