Author(s): Joao Chambel; Tiago Fazeres-Ferradosa; Filipe Miranda; Ana Margarida Bento; Francisco Taveira-Pinto; Paulo Rosa-Santos
Keywords: Laboratory facility adaptations; Wave-current flume; Passive wave absorption system; Wave reflection coefficient; Offshore Engineering
Abstract: To analyze soil-fluid-structure interactions, physical modelling is performed at laboratory facilities that vary from current flumes to wave basins. Studies of coastal protection, scour at offshore foundations, and hydrodynamic/geotechnical behavior of marine energy technologies, among others, require the use of wave and current loadings. In current-only flumes, adding waves can be quite challenging. This implies the installation of wave generation systems and passive/active absorbing systems, functioning perfectly as a whole without damaging the existing conditions. This research presents a practical study of the adaptation of a current flume to a wave-current flume at the Hydraulics Laboratory of the Faculty of Engineering of the University of Porto. The flume has been adapted to accommodate a bypass system for the current's inlet, a wavemaker wet-back wave-paddle by HR Wallingford (UK), and an absorption beach at the downstream side of the flume. The infrastructure's adaptation enabled the reproduction of solitary, regular, and irregular long-crested waves for a maximum water depth of 0.7 m with a significant wave height of 0.10 m with the potential to reproduce waves with significant wave heights of up to 0.25 m. With the adaptation works, the analysis of flow conditions and wave reflection coefficient results for a set of wave-current flow conditions is presented. Results demonstrate that the setup enables proper research on soil-fluid-structure interactions for offshore conditions. The reflection coefficient was reduced below 15 % 0.5 to 1 Hz peak frequency range, which can be optimized with novel absorption systems.