• Energy Research
• 2016-2025close

Abstract In Part I, viscous effects on bottom hinged Oscillating Wave Surge Converters (OWSCs) were investigated numerically. In the present paper (Part II), the slamming on an OWSC is studied both experimentally and numerically. Numerical simulations are performed with the Volume of Fluid (VOF) approach for capturing the interface between air and water and the dynamic mesh method for modelling the motion of the oscillating flap. Comparisons between experiments and simulations validate the numerical model. Sequences of frames from a high speed camera and from numerical results are investigated to understand the physics of the slamming process. The spatial and temporal distribution of the slam pressure on the flap is presented. The free oscillating flap and the wavemaker with prescribed motion create a multiple reflection system. The re-reflection effects on the wave field, the flap dynamics and the slamming event are discussed by comparing a series of cases from experiments and simulations.

Abstract This paper investigates the hydrodynamics of a seabed-mounted, bottom-hinged, flap-type wave energy converter in shallow water. A conceptual model of the hydrodynamics of the device has been formulated and shows that, as the motion of the flap is highly constrained, the magnitude of the wave force on the flap is the key determinant of power capture. The results from a physical modelling program have been used in conjunction with numerical data from WAMIT to validate the conceptual model. The work finds that designing the device to increase the wave force is more profitable than designing it to be tuned to the incident wave climate. As wave force is the primary driver of device performance it is shown that the flap should fill the water column and pierce the water surface to reduce decoupling due to wave overtopping. It is concluded that, in order to maximize capture factor at a typical North Atlantic site, the flap should be approximately 20–30 m wide, with large diameter rounded side edges, having its pivot close to the seabed and its top edge piercing the water surface.