Efficiency and Survivability of a Floating Oscillating Water Column Wave Energy Converter Moored to the Seabed: An Overview of the EsflOWC MaRINET2 Database

Abstract

Floating oscillating water column (OWC) type wave energy converters (WECs), compared to fixed OWC WECs that are installed near the coastline, can be more effective as they are subject to offshore waves before the occurrence of wave dissipation at a nearshore location. The performance of floating OWC WECs has been widely studied using both numerical and experimental methods. However, due to the complexity of fluid–structure interaction of floating OWC WECs, most of the available studies focus on 2D problems with WEC models of limited degrees-of-freedom (DOF) of motion, while 3D mooring effects and multiple-DOF OWC WECs have not been extensively investigated yet under 2D and 3D wave conditions. Therefore, in order to gain a deeper insight into these problems, the present study focuses on wave flume experiments to investigate the motion and mooring performance of a scaled floating OWC WEC model under 2D wave conditions. As a preparatory phase for the present MaRINET2 EsflOWC (efficiency and survivability of floating OWC) project completed at the end of 2017, experiments were also carried out in advance in the large wave flume of Ghent University. The following data were obtained during these experimental campaigns: multiple-DOF OWC WEC motions, mooring line tensions, free surface elevations throughout the wave flume, close to and inside the OWC WEC, change in the air pressure inside the OWC WEC chamber and velocity of the airflow through the vent on top of the model. The tested wave conditions mostly include nonlinear intermediate regular waves. The data obtained at the wave flume of Ghent University, together with the data from the EsflOWC tests at the wave flume of LABIMA, University of Florence, provide a database for numerical validation of research on floating OWC WECs and floating OWC WEC farms or arrays used by researchers worldwide.

Comparative study of offshore spar-buoy oscillating water column dynamic models for captured power estimation

“…Several studies investigated the performance of Oscillating Water Columns (OWCs) whether they are offshore 1 or onshore OWCs (Doyle 2020 2 ), and considering mooring system interactions. 3,4 Spar-buoy are attractive for being simple, axi-symmetrical and equally efficient at capturing energy from all directions. 5 The adoption of linear wave theory provides many benefits; Folley and Whittaker (2009) 6 reported that it allows exact solutions to be produced with relative ease for both monochromatic and mixed seas.…”

A Numerical Validation of 3D Experimental Dam-Break Wave Interaction with a Sharp Obstacle Using DualSPHysics

“…DualSPHysics [25] is an advanced meshless solver with emphasis on free-surface flow modeling and has been shown to be robust and accurate in a wide range of applications: reproducing extreme wave events [26], coastal engineering simulations [27,28], fluid-solid interaction (FSI) [29,30], wave energy converters [31][32][33][34][35], etc. The peculiarities of this solver make it suitable for dam-break simulations, since it is naturally able to handle large deformations and violent impacts that involve solid obstacles [36,37]; it follows that SPH-based numerical models could be as effective as, if not better than, the traditional methods applied to the dam failure records, such as the ones based on 2D SWEs [38,39] or the VOF-or FEM-based [40,41] models.…”

On the Development of a Novel Approach for Simulating Elastic Beams in Dualsphysics With the Use of the Project Chrono Library

“…The DualSPHysics code has been applied to several multiphysics phenomena, for example in coastal engineering simulations: to compute forces exerted by large waves on the urban furniture of a realistic promenade [2], to study the run-up on a real armour block coastal breakwater [3,4] and to simulate large waves generated by land-slide events [5]. Other successful applications of DualSPHysics are performed in the field of renewable energies, for example the simulation of Wave Energy Converters (WECs) in several contexts: from the study of the moorings and floatings dynamics [6,7,8,9], to the efficiency [10] and survivability [11] analysis when combined with closed loops [12,13], PTO systems [4,14] or non linear mechanical constraints [15]. These works present first attempts of reproducing the effects of power take-off systems through simplified, although reliable, approaches.…”