CFD analysis on the hydrodynamic performance of an Oscillating Water Column Wave Energy device with variable bottom topography*

Oscillating Water Column (OWC) device is one of the various types of Wave Energy Converters developed so far to harness energy from the Ocean waves. In the present study, the effect of sea bed slope on the hydrodynamic performance of a floating OWC device is analyzed using Computational Fluid Dynamics (CFD). An incompressible, multiphase Volume of Fluid (VOF) model is adapted with the help of a numerical wave tank (NWT) for simulating the ocean waves. The dynamic mesh technique is used to capture the motion of the device. The free surface elevation and flow characteristics are analyzed inside and outside the OWC device. The hydrodynamic capture efficiency is investigated for waves of different time periods. Four different cases of seabed slopes are studied and the results indicate a certain influence of the seabed slope on the hydrodynamic performance of the OWC device. It was observed that there is a significant rise in peak efficiency for few cases of the bottom slopes and in general, the frequency band for wave energy capture widens due to the presence of a seabed slope. This is a very important analysis from the practical viewpoint, considering the installation and operation of such devices.