Meeting Abstract

S7-1.1  Friday, Jan. 6  Robotic models of fish body and caudal fin propulsion LAUDER, G. V.*; FLAMMANG, B.; ALBEN, S.; Harvard University; Harvard University; Georgia Institute of Technology

Considerable progress in understanding the dynamics of fish locomotion has been made through studies of live fishes and by analyzing locomotor kinematics, muscle activity, and fluid dynamics. Studies of live fishes are limited, however, in their ability to control for parameters such as fish length, flexural stiffness, and kinematics. Keeping one of these factors constant while altering others in a repeatable manner is typically not possible, and it is difficult to make critical measurements such as locomotor forces and torques on live freely-swimming fishes. In this presentation we will discuss the use of simple robotic models for flexing fish bodies and the effect of changing tail shape on these models for our understanding of aquatic locomotor dynamics. A self-propelling robotic flapping-foil apparatus is used to analyze the effect of changing length, flexural stiffness, and tail shape on swimming speed and locomotor forces and torques. Altering these parameters individually reveals some surprising non-linear effects. We also quantify the wake structure behind swimming foils with volumetric particle image velocimetry, and describe the effect of heterocercal and homocercal tail shapes on wake flow patterns. One key advantage of the considerable degree of control afforded by robotic devices and the use of simplified geometries is that mathematical analyses and computational models are facilitated, as illustrated by the application of an inviscid computational model. Future work with this robotic system includes analyses of unsteady locomotor behaviors such as c-start escape responses.