Ocean Energy Systems Wave Energy Modeling Task 10.4: Numerical Modeling of a Fixed Oscillating Water Column

This paper reports on an ongoing international effort to establish guidelines for numerical modeling of wave energy converters, initiated by the International Energy Agency Technology Collaboration Program Ocean Systems. Initial results point absorbers were presented in previous work, and here we present a breakwater-mounted Oscillating Water Column (OWC) device. The experimental model is at scale 1:4 relative full-scale installation water depth 12.8 m. power-extracting air turbine modeled orifice plate 1–2% internal chamber surface area. Measurements elevation, flow through orifice, pressure difference across are compared with calculations using both weakly-nonlinear potential theory computational fluid dynamics. Both compressible- incompressible-flow models considered, effects compressibility found have significant influence motion surface. Recommendations made reducing uncertainties future campaigns, which critical enable firm conclusions be drawn about accuracy models. It well-known that boundary element method solutions linear problem (e.g., WAMIT) singular infinite frequency when panels placed directly free problematic time-domain where value added mass matrix critical, especially OWC chambers, zero-mass elements A straightforward rational procedure described replace ad-hoc this been proposed literature.