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Fluid Dynamics Seminar

Monday, Oct 23, 2006, 4:15 PM
Cullimore Lecture Hall, Room 611
New Jersey Institute of Technology

Fin Ray Design and Use in Fish Swimming

Silas Alben

Department of Engineering and Applied Sciences, Harvard University

Abstract

Fish fins have evolved over millions of years in a convergent fashion, leading to a highly-intricate fin-ray structure that is found in half of all fish species. This fin ray structure presumably arose for reasons of efficient hydrodynamic interaction. I will present a linear elasticity model of the fin ray, based on the physical picture of the ray which has emerged from past experiments. By comparing the model with more recent experiments performed in the Lauder Lab in Harvard's Biology department, we find that it captures a variety of shapes assumed by a fin under external forcing. I will then present simulations of a fully-coupled fin-fluid model which aim to help us understand fish locomotion. So far we have examined basic aspects of flow-body oscillations in high-Reynolds number flows with vorticity. This work is based on a new method for a computing the dynamics of a flexible bodies and vortex sheets in 2D flows.