Leveraging 2:1 Parametric Resonance in a Notional Wave Energy Harvester

In ocean engineering applications, parametric resonance is normally detrimental for the stability of large structures, so the vast ma- jority of effort in the literature is towards preventing and reducing it; similarly, parametric excitation is usually undesired for wave energy ex- traction too, since it often reduces the conversion ability. Conversely, this paper investigates the possibility to purposely introduce a 2:1 parametric resonance into a pitching wave energy harvester in order to inherently increase the energy absorption capabilities. Such a change in perspective is enabled by the use of a computationally efficient nonlinear hydrody- namic model (nonlinear Froude-Krylov force), that is able to articulate such a parametric instability at an early-development stage in a design- oriented simulation framework. The introduced 2:1 instability is found to be promising, since a significant amplification is obtained in the 2:1 region, where the oscillation amplitude is similar or even higher than in the 1:1 region.