Numerical modelling tool for multibody wave energy converters

Abstract

Numerical models of wave energy converters (WECs) have been successfully used since the 1970s to understand a device’s characteristics and improve its performance before advancing to costlier, higher-risk stages of development such as tank testing and sea trials. In the last decade several software packages have become available to the industry specifically for time-domain multibody WEC modelling using potential flow theory. One of these tools is InWave, developed by Innosea, which is based on a reduced-coordinate multibody dynamics solver. However, one of the main challenges in developing a WEC modelling tool is the fact that the wave energy sector has not yet converged on a particular technology and there are many different designs currently in development, featuring a wide range of working principles. This thesis presents a novel WEC modelling tool: InWave-HOTINT, which uses a third-party multibody dynamics code (HOTINT) based on a redundant coordinate multibody dynamics method. This approach enables InWave-HOTINT to model a much wider range of mechanical topologies - including WECs featuring closed mechanical loops, multi- DoF PTOs and net mooring systems. The thesis describes the development and verification of the tool, as well as a demonstration of some of the new capabilities via a model based on the Albatern S12 WEC.