The work to be presented concerns the preliminary hydrodynamic simulation of an overtopping wave energy converter formed by a permeable ramp that discharges to a reservoir. The water free surface of this reservoir is about 3 m above the sea level and discharges to the sea through a low-head hydraulic turbine. As a first approach to model this device, an isolated inclined ramp with varying permeability is used. The numerical model is based on the two-dimensional RANS (Reynolds Averaged Navier-Stokes) equations and uses the VOF technique to describe the free surface. An experimental validation of the code is presented using experimental data on wave transformation at vertical and inclined (impermeable and perforated) walls by Muttray and Oumeraci (2001). Predictions of wave transmission, reflection, breaking and wave energy dissipation are presented. The validated model is then applied to several structure configurations in order to analyze the influence of relevant geometric parameters in potential energy accumulation and energy production.
An overtopping wave energy converter is either a bottom standing or a floating offshore wave energy converter formed, basically, by a permeable ramp, a reservoir and low-head hydraulic turbines. The waves run up the ramp and fall into the reservoir, placed approximately 3 m above the sea level. The resulting pressure height is utilised for power production discharging to the sea through a number of low-head hydraulic turbine. A system of valves avoids the water to flow from the reservoir to the sea trough the permeable ramp. This work is a preliminary numerical study using a model named Cobras. This code is a two-dimensional numerical model that solves the Reynoulds Avereged Navier Stokes (RANS) 2DV equations, with threedimensional k-ε turbulence model and uses the VOF technique to describe the free surface.
