Mixing Efficiency of Swimming Animals in Stratified Fluids

Monday, March 23, 2009
9:00 - 10:00 AM
Room 229 Norris Hall

Ms. Kakani Katija Young
Graduate Aeronautical Laboratories and Bioengineering, California Institute of Technology, Pasadena, CA 91125

The potential role of animal-fluid energy interactions in ocean mixing is a topic of increasing study that has been limited by the need for data at the scale of individual animals. Previous findings suggest that the energetic input by swimming animals to the ocean mixing energy budget may impact mixing at the same level as winds and tides, whose respective rates of kinetic energy dissipation are of the same order of magnitude. However, these results equate dissipation of mechanical energy with mixing; not all mechanical energy that is dissipated goes into mixing a fluid. The mixing efficiency should instead be an indicator of mixing. A method that determines the mixing efficiency of swimming animals will be presented. This method combines the techniques of DPIV, PLIF and dye visualizations. This methodology is then applied to multiple swimming cycles of Mastigias sp. (a native Palauan jellyfish species) to answer whether mechanical energy at small animal scales can achieve any substantial mixing before it is dissipated as heat.

Biographical Sketch: Kakani Young received a B.S. in Aeronautics and Astronautics at University of Washington. She received an M.S. in Aeronautics at California Institute of Technology and will be completing a Ph.D. in Bioengineering at the same institution. As an undergraduate, Kakani and a team of peers successfully conducted a fluids experiment on board the “Vomit Comet” as part of NASA’s Reduced Gravity Student Flight Opportunities Program. Later Kakani became the state of Washington’s representative for the NASA Academy at NASA Ames Research Center. During her Ph.D. she became a certified research diver and has conducted SCUBA diving field expeditions in Friday Harbor, WA, Woods Hole, MA, Croatia and Palau. Kakani is a recipient of both the ASEE National Defense Science and Engineering Graduate Fellowship and the National Science Foundation Graduate Student Research Fellowship.

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