Numerical investigation of wave interactions in an experimental wave-energy converter using OpenFOAM

Abstract

In this paper, OpenFOAM wave generation and active wave absorption boundary conditions were used to simulate wave interaction of a specific experimental wave energy converter (WEC) with equilibrium buoys and two power take-off systems that work in parallel, over a broad range of wave conditions. Two solitary and cnoidal wave generation boundary conditions for three different wave heights were implemented at the inlet to generate waves. The validation phase included a comparison of free-surface with numerical results of solitary and cnoidal waves generation at the flume. To investigate the impact of equilibrium buoys, wave flow around the wave energy converter was simulated for two cases. In the first case, WEC was considered as a single box, and in the second, two equilibrium buoys were added to the WEC. By comparison of these two cases, we discovered that although equilibrium buoys decrease the horizontal force on the main box, they cause the production of two efficient vertical forces. One of these forces moves the front equilibrium buoy generating electricity individually from the main box mechanism, and the other vertical force is applied to the back equilibrium buoy accelerating the rotation of the main box. Overall, wave energy absorption is enhanced by using the equilibrium buoys.