Modelling of a Damped Generic Submerged Spherical Wave Energy Converter in Resonance

Understanding the importance of nonlinear effects on wave energy converters (WECs) is key to an accurate prediction of the power take-off (PTO) and design parameters during the development stage. The current study applies a fully nonlinear CFD model to analyse the performance of a fully submerged spherical WEC operating in heave. Three optimal restoring force coefficient values are used based on the incident wave frequencies along with the coinciding optimum radiation damping coefficient derived from previous linear models. CFD PTO results from the WEC cases are shown, quantifying the impact of nonlinear effects. Results show distinct variations between the linear and CFD approaches to modelling a WEC due mainly in part to interactions between the free surface and the WEC.