SUMMARY

Although it is estimated that 94% of all animals are aquatic species and the bottom depths of the oceans contain the most unique topography on the planet, there is limited information on the global ocean circulation patterns and ecosystems. Currently, to gather more information about the deep depths of the oceans, scientists often use underwater and surface human-operated or autonomous vehicles. However, many of these vessels only have one propulsion system and have rudimentary maneuverability capabilities. Moreover, if this propulsion system fails, many of these vessels have a risk of being nonrecoverable or are expensive to recover. As a result, ocean researchers are looking, instead, to deploy small “swarms” of less expensive autonomous vehicles, similar to a school of fish, in order to survey larger portions of these vast bodies of water with less probability of failure.

The objective of this proposal is to investigate “multi-oar” propulsion at intermediate Reynolds number (Re) via studying several biological species and biological models. The overarching objective is to provide insight to the design of low-cost autonomous vehicles to be used in swarms similar to a fish schools, instead of a singular, larger, expensive autonomous vehicle. As these engineered aquatic devices scale down in size, the Re of the flow transitions from a well-studied turbulent inertia-dominated regime to a less understood intermediate flow regime where inertial and viscous forces contribute to behavior of the flow. Tomographic Particle Image Velocimetry (tomo-PIV) is used to quantify and compare the hydrodynamics of swimming behavior of several species of free swimming planktonic malacostracan crustaceans, i.e., krill and mysids, as well as the flow behavior of small multi-limbed bio-inspired aquatic robots. Specific objectives are described, and the results from this study will provide insight on the locomotion kinematics and flow behavior of seldom-studied, highly maneuverable free swimming malacostracan crustaceans. Preliminary kinematics, velocity, and vorticity field results are presented for the caridoid escape response, a fast-start mechanism unique to malacostracan crustaceans, in Antarctic krill, Euphausia superba.