A bioinspired submersible propelled by a fluttering, fluid-conveying tail was designed and analyzed. A simple model of the submersible was created by treating the rigid hull of the submersible as a rigid body boundary condition on the fluid-conveying tail. Curves of neutral stability were determined in the internal/external velocity parameter space for several values of rigid body mass, and the thrust produced by these neutrally-stable waveforms was determined using Lighthill's methods. The power required to produce these waveforms and their efficiency were also determined. The efficiency was found to be in excess of 50%, a figure comparable to a small marine propeller, but far below the 90% quoted in fish propulsion literature. A more general model of the submersible which removed many of the linearizing assumptions made in the simplified model was also developed and solved numerically. This model is comprised of the equations of motion for a non-inertial frame fixed on the rigid head of the submersible and the equations of motion for a fluid-conveying tail within that non-inertial frame. Simulations were made using several flexible tail geometries, as well as for a rigid tube and a rigid tail which was dimensionally identical to one of the geometries. The forward speed of the fluttering flexible tail configuration was found to be higher than than that of the rigid tube configuration for one geometry, and higher than that of the rigid tail for most geometries. A prototype of this submersible was constructed, and qualitative features and findings of the general model were verified. The general model was also extended to incorporate a time-variable velocity of the conveyed fluid, and a functional description of this velocity was found which caused the submersible to turn without the incorporation of additional actuators on the tail or hull-mounted fins.
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