Combining Multi-body Dynamics and Potential Flow Simulation Methods to Model a Wave Energy Converter

Abstract

Numerical simulations that predict the dynamics and performance of wave energy converters (WECs) require the simulation of complex fluid-structure interactions between a WEC device and the wave environment. Navier- Stokes computational fluid dynamics (CFD) simulations and fully time-domain boundary integral equation methods (BIEMs) can be coupled with multi-body dynamics solvers to simulate these problems. However, the computational resources that are required to perform these types of high-fidelity simulations are significant, precluding the use of CFD and time-domain BIEM for design optimization. One method for reducing the numerical complexity of WEC simulations is to model the hydrodynamics using frequency- domain simulations, while model the dynamic motion of the WEC device in the time-domain using multi-body dynamics methods. The primary objective of the work presented herein is to develop such a numerical tool using the multi-body solver SimMechanics and the frequency-domain hydrodynamics code WAMIT. The numerical tool was developed so that WEC devices comprised of arbitrarily connected bodies, power-take-off (PTO) systems, and mooring systems can be simulated in operational sea states, where the wave environment can be modeled under linear assumptions. The remainder of this paper describes the development and verification of the numerical tool.