Abstract
Wave energy is one the most promising non-fossil fuel energy sources. Up to this date, several forms for the transformation of wave energy into usable electricity have been proposed. The flap-type oscillating wave surge converter is one of the most efficient devices that have been developed and tested. A comprehensive characterization of its hydrodynamic performance is an important step towards the improvement of this encouraging technology. The viscous phenomena associated with wave energy converters are usually integrated into a drag coefficient value that is recognized as a major source of uncertainty in the final performance assessment. In real fluid hydrodynamics, viscous effects are intimately connected with the vorticity of the flow and the vorticity dynamics at solid body boundaries is the main feature of the flow that determines the relative magnitude of the viscous effects. In this work, we use computational fluid dynamics to study the boundary vorticity flux in an oscillatory flow at low Keulegan-Carpenter numbers and characterize the associated viscous phenomena, such as vortex shedding