Numerical simulation of a floating-type point absorber wave energy converter

Abstract

Wave energy converters (WEC) have been researched extensively to harvest large amounts of untapped ocean renewable energy. Floating-type point absorbers are a type of WEC that converts the ocean wave energy to electrical energy, by utilizing the relative motion of multi-body system mainly consisting of a floating section and a reaction section. The design of floating-type point absorbers is not straightforward and needs special attention to understand the dynamics of the multi-body system, and power take-off (PTO) mechanism placed in the reaction section. The purpose of this study is to develop a numerical simulation tool which can help understand various dynamics of a floating-type WEC and aid in the practical design of PTO systems. The PTO mechanism is represented using a spring-damper system and theoretical modelling of mean absorbed power is presented. The numerical simulation is developed in Orcaflex and is carried out on a demonstration model to show the usefulness of the developed tool. The heave displacement shows the effect of damping (PTO) on the motion response of the floating-type WEC. It is found that the maximization of absorbed power is possible using the developed simulation tool for a specific sea state. Furthermore, the results show the potential use of the developed tool for other floating-type WEC concepts.