3D Numerical Modelling of Oscillating Water Column Wave Energy Conversion Devices: Current Knowledge and OpenFOAM® implementation

The Oscillating Water Column (OWC) is one of the oldest and simplest concepts for wave energy conversion. However, the device optimization is still required as a fundamental step towards the technology commercial scale diffusion. Numerical modelling, validated and calibrated with results from physical tests, is an essential tool, allowing the study of more configurations than those practically feasible with physical modelling and measurement in an undisturbed flow field. In this study, the state of the art of OWC numerical modelling as well as a CFD model (with turbulence modelling) of an OWC device implemented in OpenFOAM® are presented. The multiphase (air-water) model adopts a Volume of Fluid (VOF) method to track the air-water interface. The implemented model solves the incompressible 3D Navier-Stokes equations, using Large Eddy Simulation (LES) for turbulence modelling. Preliminary results are compared to physical tests performed on the same configurations in a physical wave flume. The approach seems to be promising for the simulation of the different steps of energy conversion hydraulic chain, allowing the evaluation of the conversion efficiency and a deeper understanding of the relevant processes involved in the wave-structure interaction.