Flapping foil propulsion for shipping vessels

Fish and cetaceans have evolved over millennia to be highly-efficient swimming machines, propelling themselves with what engineers would call a "flapping hydrofoil." In some cases, flapping foil propulsion can be more efficient than a conventional screw propeller, which suffers efficiency losses due to wake rotation (swirl) and due to the limited area that can be swept by the blades. On the other hand, a hydrofoil can better take advantage of the usable area behind the ship, which results in higher ideal efficiencies. In addition, the flapping motion can be made to develop a highly-efficient jet-type wake, similar to that produced by the swimming animals. The engineering challenge is to design a mechanical system that mimics the biological one, while still being economical, manufacturable, and durable. Cycloidal propulsion is one promising engineering solution that yields the efficiency advantages of flapping foil propulsion but the mechanical simplicity (and correspondingly low cost) of the screw propeller. Current projects include systems engineering and economic analysis, mathematical modeling of a notional cycloidal propulsion system, computational fluid dynamics analysis of the hydrodynamics and resulting propulsive efficiency, and experimental validation testing on a scale-model prototype.

Faculty contact: Brenden Epps