Investigation of Wave Reflection at Different Water Heights in a Wave-Current Flume

Wave-current flumes are an invaluable research tool for physical modelling studies of coastal, marine, offshore and hydraulic phenomena. However, wave reflection is a commonly observed model effect that can lead to discrepancies between model and prototype behavior. This effect can be minimized by dissipating the wave energy downstream of the study area, and it can ultimately be neglected if the wave reflection coefficient is kept below the guideline value of 15%, ideally below 10%. Dissipation of wave energy can be achieved by using a wave dissipation system in the downstream portion of the flume. A novel configuration of the wave dissipation system with cork filled plastic net rolls was designed for a model water height of 0.4 m and installed in the wave-current flume of the Hydraulics Laboratory of the Faculty of Engineering of the University of Porto (FEUP). The current study aims to evaluate the effectiveness of the configuration of this system for different water heights (up to 0.40 m water height) using a 1:50 model of the hydrodynamic prototype conditions in the North Sea, as part of ongoing studies of the laboratory on the design of offshore wind farms. According to the study findings, the wave reflection coefficient can be kept below 15% at various water heights by creating enough turbulence inside the cork-filled plastic net rolls. In addition, the present work provides evidence that cost-effective and practical solutions can be implemented to achieve effective wave dissipation systems at a much lower cost than other technically complex solutions such as the parabolic metallic dissipation systems.