Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (pages 197-209). / Jumping for aerial prey from an aquatic environment requires both propulsive power and precise aim to succeed. Archer sh, better known for their spitting abilities, will jump multiple body lengths out of the water for prey capture, especially in competitive foraging scenarios. Prior to jumping, archer sh aim from a stationary position with the snout located directly below the water's surface. Rapid acceleration to a ballistic velocity sucient for reaching the prey height occurs with a mere body length to travel before the sh leaves the water completely and experiences a thousandfold drop in force-producing ability. In addition to speed, accuracy and stability are crucial for successful feeding by jumping. The combination of these factors in the archer fish's unique jumping strategy may bring new insights to the design of underwater vehicles capable of spatially-constrained acceleration or water exit. This thesis examines the hydrodynamic mechanisms underlying the archer fish's jumping abilities. First, behavioral and kinematic trends from five specimens are presented to elucidate key jump attributes. Modulation of oscillatory body kinematics and use of multiple ns for force production are identied as methods through which the sh can meet requirements for both acceleration and stabilization in limited space. In addition, flow field measurements made using planar particle image velocimetry (PIV) reveal vortical wake structures originating from the caudal, dorsal, anal, and pectoral ns. Exact n interactions cannot be identied from a single slice through the wake, suggesting a need for further three-dimensional study. To address this limitation, a volumetric particle image velocimetry system meeting specfic requirements for the study of jumping archer sh is developed. The multi-camera measurement system is based on the synthetic aperture particle image velocimetry (SAPIV) technique. The SAPIV system provides time-resolved measurements of both the fish's wake and its aerial trajectory, working within the optical access constraint created by the sh jumping from directly below the water's surface. Image processing improvements to measure fin-fin and n-body interactions despite partially-occluded tracer particles are also implemented. The capabilities of the system to make time-resolved measurements of multiple ns during a single jump are demonstrated. To utilize the 3D velocity field data provided by this technique, approaches to quantitative wake analysis suitable for isolated three-dimensional wake structures and interacting multi-vortex wakes are presented. Finally, detailed 3D SAPIV measurements of ow from the archer fish's dorsal, anal, and caudal ns at jump onset are obtained. Quantitative wake measurements reveal how variations in tail kinematics relate to thrust production throughout the course of a jumping maneuver and over a range of jump heights. Measurements also highlight momentum ux into the wake emanating from the upstream dorsal and anal ns. These ow structures augment the caudal n wake during subsequent tailbeats. By performing measurements in 3D, the timing, interactions, and relative contributions to thrust and lateral forces from each n can be evaluated, elucidating the complex hydrodynamics that enable archer sh water exit. / by Leah Rose Mendelson. / Ph. D.
| Identifer | oai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/111693 |
| Date | January 2017 |
| Creators | Mendelson, Leah Rose |
| Contributors | Alexandra H. Techet., Massachusetts Institute of Technology. Department of Mechanical Engineering., Massachusetts Institute of Technology. Department of Mechanical Engineering. |
| Publisher | Massachusetts Institute of Technology |
| Source Sets | M.I.T. Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 209 pages, application/pdf |
| Rights | MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission., http://dspace.mit.edu/handle/1721.1/7582 |
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