High-fidelity modelling of a simplified hinged-raft WEC: a CFD approach

The use of high-fidelity Computational Fluid Dynamics (CFD) has become increasingly popular in the wave energy sector for investigating device dynamic behaviours which helps to inform design choices. Compared to low-fidelity models, CFD is capable of capturing highly non-linear behaviours such as viscous effects and turbulence; compared to tank testing, CFD has the potential to simulate different wave conditions and geometries cost-effectively. However, little example exists in current literature for the setup of a two-body floating hinged-raft Wave Energy Converter (WEC) such as a Mocean Energy device using CFD. This paper aims to outline the basic workflow and provide a methodology for the CFD simulation setup of a simplified hinged-raft geometry using the OverInterDyMFoam solver in OpenFOAM, the modelling practice for handling the interface between the two hulls will also be addressed. The floating hinged-raft will be simulated in four different Overset (OS) mesh configurations, results will be compared between the different setups. The impact of different gap sizes between the bodies has on the responses of the device will also be explored. This work will help inform the model setup of a hinged-raft device with more complicated geometries, which will be another step forward towards device survivability studies.