A free surface model for the numerical simulation of oscillating water column systems

Abstract

The aim of this work is to propose and validate a numerical model that represents the hydrodynamic behavior of an Oscillating Water Column (OWC) device, that has been shown to be one of the most promising ways to extract energy from ocean waves: successful demonstrative set-up have been realized both on shore based structures (LIMPET device in Scotland and PICO plant in Azores) and on anchored floating ones (OE Buoy in Ireland) [1]. A Level Set scheme was employed to track the free moving interface in an incompressible, transient two-phase flow, globally governed by the Navier-Stokes and the mass conservation equations. After being validated, the model was used to investigate the interaction of linear waves with a submerged air chamber; several set-up were analyzed by monitoring the characteristics magnitudes, in order to assess the accuracy of the model and to optimize the hydrodynamic efficiency of the device. In the second part, a single phase Level Set method was developed and used to simulate the same problem.