The title of this project is ‘Nonlinear Rock and Roll – Modelling and Control of Parametric Resonance in Wave Energy Converters’. The over-arching aim is to catalyse increased research into parametric resonance (PR) within wave energy and other offshore renewable energy fields.
The concept of resonance is well known in the study of wave energy converters (WECs). In comparison, PR has received virtually no attention, and is often unexpected since it is a nonlinear phenomenon not predicted by the linear/frequency domain models traditionally favoured in WEC research and analysis. Whereas normal resonance causes the oscillations of a system to grow linearly with time, PR causes an exponential increase in oscillation amplitude, and therefore has great potential to be either detrimental or beneficial to a WEC performance. For certain classes of WECs, PR can lead WEC instability and decreased performance, by transferring energy from the primary mode of motion into other modes. Alternatively, for other types of WECs designed to extract power from the parametrically resonating modes of motion, triggering PR could result in increased energy capture and represent a game-changing approach to improving WEC performance.
To achieve the over-arching goal, the project focuses on the following specific objectives:
1) Demonstrate novel control techniques to either mitigate or harness PR for different classes of WECs.
2) Provide opensource tools for modelling and analysing PR in WECs, to aide the wave energy community in overcoming the barriers surrounding the advanced nonlinear methods required to investigate PR.
3) Strong communication, dissemination and exploitation activities. Providing information to the wave energy community and connections with researchers from other disciplines with relevant knowledge and experience, such as Nonlinear Dynamics, Shipping and other Offshore Engineering fields.