Advanced numerical modeling of OSWEC using OpenFOAM and Overset mesh strategy

Minge Jiang, Danesh Tafti

Abstract:

Ocean wave energy has gained significant attention in the renewable energy sector, leading to the development and study of various wave energy converters (WECs). Among these, the Oscillating Surge Wave Energy Converter (OSWEC) has demonstrated a higher power capture ratio and easier operation and installation. High-fidelity models, such as Computational Fluid Dynamics (CFD), offer more accurate predictions for realistic design needs. This research employs OpenFOAM, an open-source CFD software, utilizing the overset mesh strategy coupled with built-in wave models and a numerical wave tank (NWT) to simulate multiphase flow and rigid body dynamics of the OSWEC, and to investigate the hydrodynamic characteristics of the system. The overset mesh strategy uses a fixed overset mesh attached to the rigid body to prevent errors caused by the grid deformation from dynamic mesh and reduce computational costs. The CFD model is validated against existing experimental and CFD results from the literature, yielding good agreement. Convergence tests demonstrate that a minimum cell per wave height (CPH) is necessary to reduce numerical noise. The overset mesh strategy is shown clearly advantageous for fluid-structure interaction (FSI).