Advanced Wave-to-Wire OWC model in WEC-Sim

Accurate numerical models are crucial for the development of wave energy converter (WEC) technologies, providing the means for power production and lifetime assessment, site selection, and design of mooring lines, PTO systems and controllers, among other aspects. The present project aims at developing a wave-to-wire numerical model for floating oscillating water column (OWC) devices based upon the Wave Energy Converter SIMulator (WEC-Sim) platform. To that end, nonlinear hydrodynamics, considering viscous and nonlinear Froude-Krylov effects were implemented, and new capabilities were articulated into the WEC-Sim platform, incorporating thermos-aerodynamic effects for the air-turbine. A numerical model of a wave-to-wire controller was developed in this project, and its efficiency and performance have been tested numerically. In addition to this, a mooring system was also included in the numerical model. The hydrodynamic coefficients for the OWC were calculated using different numerical solvers: ANSYS, WAMIT, Capyatine, and NEMOH. This paper also contrasts two distinct modeling approaches. In the first approach, the WEC's main structure and the OWC are modeled as separate entities. In the second, the WEC and OWC are considered a single body, with the free surface of the oscillating water column added as an extra degree of freedom. Nonlinear hydrodynamic effects, including viscosity and nonlinear Froude-Krylov forces, are incorporated to assess their impact on the numerical analysis of OWC systems.