Session: 03-07-01: Innovative Product Design and Manufacturing

Paper Number: 113114

113114 - Analysis of Hydrodynamic Loading on Shark Species to Inform Design of Low Drag Satellite Telemetry Tags 

Sharks are apex predators which are pivotal to nearly all marine ecosystems and many species are highly migratory, traveling thousands of miles throughout their lifetimes. Shark movement patterns are studied using satellite telemetry tag devices. Tags are typically attached to the dorsal fin of a shark and, depending on the type of tag, may either send a signal each time the dorsal fin breaks the surface of the water or, in the case of pop-up archival tags, are designed to detach from the shark after a certain period of time and float to surface where they may then communicate with the satellite. While spatiotemporally resolved movement data are highly valuable to studying shark ecology and conservation, satellite telemetry tags do result in hydrodynamic loading which produces a drag force on the shark, potentially influencing their behavior leading to incorrect movement analysis. Since tags change the streamlined body shape of animals, they may influence swimming patterns, especially at high speeds since drag increases with velocity. In this study, we sought to better understand baseline shark hydrodynamics that then could be used to evaluate additional hydrodynamic loading from satellite telemetry tags of different form factors. We used existing 3D digital models of three shark species—the Great Hammerhead (Sphyrna mokarran), Blacktip Reef (Carcharhinus limbatus), and Caribbean Reef (Carcharhinus perezii)—to assess these effects and influence future tag design. This paper explores flume testing at the OSU O.H. Hinsdale Wave Lab as a new method to improve CFD validation by using a cart apparatus that glides along the top of the flume at controlled velocities to simulate average cruising speeds of each shark species at angles of attack of 0, 12, and -12 degrees for neutral, rising, and diving movement patterns, respectively. Using principles of similitude, shark models were rescaled to account for the size of the 3-meter long flume and resulting forces were measured using a IP68 Gamma Transducer strain gauge load cell mounted to the cart apparatus. We compared the drag and lift measurements from the flume tests to the drag and lift coefficients generated using computational fluid dynamics (CFD) simulations in STAR-CCM+ using the same 3D models of the sharks species, velocities, and angles of attack. We found that the mean percent error was -13.67% +/-57.38%  standard deviation for the drag coefficient and -53.10% +/- 87.38% standard deviation for the lift coefficient across the 3 species and angle of attack. Future work incorporates the addition of scaled digital satellite tags on shark models to compare to untagged data with the intent of informing subsequent tag designs.

Presenting Author: Bianca Hansen Oregon State University

Presenting Author Biography: Bianca Hansen (E.I.T.) is a recent Oregon State University graduate with a BS in Mechanical Engineering and a Humanitarian Engineering Concentration. She has research experience in fluid dynamics, pyrolysis, and thermodynamic energy generation.

Authors:

Brooke Aduviri Oregon State University
Bianca Hansen Oregon State University
Cassandra Wettstein Oregon State University
Susan Piacenza Oregon State University
Joseph Piacenza Oregon State University
Pedro Lomonaco Oregon State University