Hydrodynamic Simulation of a Point Absorber Wave Energy Converter Using CFD in OpenFOA

Abstract

This study presents a hydrodynamic simulation of a point absorber-type wave energy converter, specifically a buoy, using computational fluid dynamics (CFD) implemented through the OpenFOAM software. The simulation is performed under linear wave conditions, considering monochromatic waves. Due to the lack of native support in OpenFOAM for Octree-type mesh generation, a custom "in-house" meshing strategy was developed using a combination of polyhedral and hexahedral cells. This approach allowed for a reduction in the total number of cells while preserving accuracy in critical regions of the domain, thereby improving the computational efficiency of the model. To mitigate wave reflections at the domain boundaries, a numerical beach was implemented and calibrated using the three-point method to effectively absorb the incident wave energy. A wave reflection test was carried out to characterize the hydrodynamic response of the buoy, giving results comparable to those obtained through reference Boundary Element Method (BEM) simulations, thus validating the accuracy of the proposed approach. Finally, resistive and reactive control strategies were incorporated into the simulation of the power take-off system, and the results were compared with those produced by the WEC-Sim solver, which is widely validated in the literature for linear models. The outcomes demonstrate a good level of agreement, confirming the capability of the developed CFD model as a viable and complementary tool for the analysis of wave energy conversion devices.