Abstract
This paper describes experimental research on a floating moored Oscillating Water Column (OWC)-type Wave-Energy Converter (WEC) carried out in the wave flume of the Coastal Engineering Research Group of Ghent University. This research has been introduced to cover the existing data scarcity and knowledge gaps regarding response of moored floating OWC WECs. The obtained data will be available in the future for the validation of nonlinear numerical models. The experiment focuses on the assessment of the nonlinear motion and mooring-line response of a 1:25 floating moored OWC WEC model to regular waves. The OWC WEC model motion has 6 degrees of freedom and is limited by a symmetrical 4-point mooring system. The model is composed of a chamber with an orifice on top of it to simulate the power-take-off (PTO) system and the associated damping of the motion of the OWC WEC model. In the first place, the motion response in waves of the moored floating OWC WEC model is investigated and the water surface elevation in the OWC WEC chamber is measured. Secondly, two different mooring-line materials (iron chains and nylon ropes) are tested and the corresponding OWC WEC model motions and mooring-line tensions are measured. The performance of these two materials is similar in small-amplitude waves but different in large wave-amplitude conditions. Thirdly, the influence of different PTO conditions is investigated by varying the diameter of the top orifice of the OWC WEC model. The results show that the PTO damping does not affect the OWC WEC motion but has an impact on the water surface elevation inside the OWC chamber. In addition, an unbalanced mooring configuration is discussed. Finally, the obtained data for a moored cubic model in waves are presented, which is a benchmarking case for future validation purposes.
Highlights
The Oscillating Water Column (OWC) is a Wave-Energy Converter (WEC) which mainly consists of a hollow chamber, open below the water level, in which a column of water is forced to oscillate once excited by the external incident waves
The present paper focuses on an experimental study of a slack-moored floating OWC WEC model in a wave flume
The present study focuses mainly on the response of the motion and mooring-line tensions of the floating OWC WEC and the BOX model subjected to unidirectional regular waves
Summary
The Oscillating Water Column (OWC) is a Wave-Energy Converter (WEC) which mainly consists of a hollow chamber, open below the water level, in which a column of water is forced to oscillate once excited by the external incident waves. Experimental studies are seen in the investigation of moored floating OWC WECs, for example, Correia da Fonseca et al [18] studied the dynamics, energy extraction, and mooring system performance of the spar-buoy OWC WEC He et al [19] presented a series of experiments of an OWC WEC integrated to floating box-type breakwaters, primarily with a focus on coastal protection. As the nonlinear numerical models are becoming increasingly popular for the simulation of floating moored OWC WECs, their validation using experimental data is crucial Such experimental studies are rarely seen in the literature. A second objective of this work is to provide open access experimental data for the validation of numerical models currently under development in the wave-energy research community.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
