Numerical Modelling of Fixed Oscillating Water Column Wave Energy Conversion Devices: Toward Geometry Hydraulic Optimization

The Oscillating Water Column (OWC) is one of the simplest and most studied concepts for wave energy conversion. The commercial scale diffusion of the OWC technology is, however, strongly dependent upon the device optimization. Research at a fundamental level is therefore still required. Analytical, numerical and experimental models are necessary tools for advancing in the knowledge of the system and thus promoting its passage at the commercial level. In this work, a simplified frequency domain rigid piston model has been applied to preliminary select expected ranges of air pressures and air velocities for the instrumental set up of laboratory experiments. The set up of a Computational Fluid Dynamic (CFD) model implemented in the open source OpenFOAM®1 environment is then presented. The multiphase model solves incompressible 3D Navier-Stokes equations, using Large Eddy Simulation (LES) for turbulence modelling, and adopts a Volume of Fluid method (VOF) to track the air-water interface. A preliminary validation of the model with physical tests data is conducted. The numerical approach seems to be promising for an accurate simulation of the OWC device energy conversion process. Hence, the validated model can be a useful research tool for different problems, particularly for systematic parameter studies to extend the range of conditions tested in the laboratory.