The Mechanics of Fast-Start Performance of Pike Studied Using a Mechanical Fish
Author(s)
Feng, Chengcheng
Bonafilia, Brian R.
Modarres-Sadeghi, Yahya
Triantafyllou, Michael S
Date Issued
November 2011
Journal
ASME 2011 International Mechanical Engineering Congress and Exposition
Publisher
ASME International
Citation
Feng, Chengcheng, Brian R. Bonafilia, Yahya Modarres-Sadeghi, and Michael S. Triantafyllou. “The Mechanics of Fast-Start Performance of Pike Studied Using a Mechanical Fish.” ASME 2011 International Mechanical Engineering Congress and Exposition, 11-17 November, 2011, Denver, Colorado, USA, ASME, 2011. © 2011 ASME
Version
Final published version
Abstract
A northern pike (Esox lucius) is capable of achieving a maximum instantaneous acceleration of 25g, far greater than that achieved by any manmade vehicle. In order to understand the physical mechanisms behind achieving such high accelerations, we have built a mechanical fish to emulate the motion of a pike, a fast-start specialist. A live pike bends its body into either a C-shaped or an S-shaped curve and then uncoils it very quickly to send a traveling wave along its body in order to achieve high acceleration. We have designed a mechanical fish whose motion is accurately controlled by servo motors, to emulate the fast-start by bending its body to a curve from its original straight position, and then back to its straight position. Furthermore, this mechanical fish is designed to be adjustable in swimming pattern, tail shape, tail rigidity, and body rigidity, making it possible to study the influence of all of these parameters on the fast-start performance. Peak accelerations of 2.0 m/s2 and peak velocities of 0.09 m/s are measured. Although the maximum accelerations and velocities observed in our mechanical fish are smaller than those of live fish, the form of the measured acceleration signal as function of time is quite similar to that of a live fish. The hydrodynamic efficiencies are observed to be around 12%, and it is shown that the majority of the thrust is produced at the rear part of the mechanical fish - similarly to the live fish. Copyright © 2011 by ASME.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
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Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1115/IMECE2011-65035
