Nonlinear Ocean Energy Harvester

Abstract

The scientific community has worked to extend communication networks, human safety programs, and environmental monitoring systems across continents, but has struggled to accomplish these same goals beyond the shoreline. Lack of offshore power is the greatest barrier restricting us from exploring the ocean because it is difficult to operate sensors without a reliable power source. Wave energy harvesting has been investigated as a solution; however, current methods have many shortcomings. Traditional ocean energy harvesters (e.g. buoys) extract energy from ocean waves by capturing the change in potential energy as the buoy travels vertically along the wave. A linear design, this type of harvester has a theoretical maximum based on the wave height that limits its usefulness to high amplitude waves within a narrow range of frequencies [5, 1, 2]. My research looks to design nonlinearity into this system by allowing the harvester to capsize as it bobs along the waves and converting that rotary mechanical energy into electricity. This degree of freedom increases the harvester’s theoretical maximum and broadens its usefulness to waves that are multi-frequency, stochastic, and varying in intensity [6, 8, 7, 4, 3]. My goal is to model the dynamics of this system so that I can optimize methods for triggering rotational instability to design inexpensive, reliable, nonlinear ocean energy harvesters.