Resonant behaviour of an oscillating wave energy converter in a channel

Abstract

A mathematical model is developed to study the behaviour of an oscillating wave energy converter in a channel. During recent laboratory tests in a wave tank, peaks in the hydrodynamic actions on the converter occurred at certain frequencies of the incident waves. This resonant mechanism is known to be generated by the transverse sloshing modes of the channel. Here the influence of the channel sloshing modes on the performance of the device is further investigated. Within the framework of a linear inviscid potential-flow theory, application of the Green theorem yields a hypersingular integral equation for the velocity potential in the fluid domain. The solution is found in terms of a fast-converging series of Chebyshev polynomials of the second kind. The physical behaviour of the system is then analysed, showing sensitivity of the resonant sloshing modes to the geometry of the device, that concurs in increasing the maximum efficiency. Analytical results are validated with available numerical and experimental data.Key words: Authors should not enter keywords on the manuscript, as these must be chosen by the author during the online submission process and will then be added during the typesetting process (see http://journals.cambridge.org/data/relatedlink/jfm-keywords.pdf for the full list)

Motion-resonant modes of large articulated damped oscillators in waves

“…In the literature, the flap-type absorber theory has been extensively validated against numerical and experimental data for several layouts of practical interest. Renzi and Dias (2012) first validated the model for a single flap in a channel with respect to numerical data obtained at Queen's University Belfast (QUB, U.K.) with the commercial software WAMIT, for monochromatic in-cident waves. Renzi and Dias (2012) also showed good agreement between the flap-type absorber results and the wave tank data obtained at QUB during an experimental campaign on the Oyster WEC, again in monochromatic waves.…”

“…Renzi and Dias (2012) first validated the model for a single flap in a channel with respect to numerical data obtained at Queen's University Belfast (QUB, U.K.) with the commercial software WAMIT, for monochromatic in-cident waves. Renzi and Dias (2012) also showed good agreement between the flap-type absorber results and the wave tank data obtained at QUB during an experimental campaign on the Oyster WEC, again in monochromatic waves. Renzi and Dias (2013a) validated their model of an infinite array of flap-type absorbers in the open ocean against numerical results obtained with a finite-element numerical model developed by the University of Roma Tre (Italy).…”

Weakly nonlinear theory for oscillating wave surge converters in a channel

“…Because of their ability to capture energy with large efficiency, these converters have received significant attention in recent years, leading to analytical theories (Linton & McIver 2001;Mei, Stiassnie & Yue 2005) and experimental campaigns (Folley, Whittaker & van't Hoff 2007;Henry et al 2010). Renzi & Dias (2012, 2014 have developed a semi-analytical theory based on a hypersingular integral equation approach to investigate the hydrodynamic behaviour of a 'thin gate' in a channel and in open sea. Michele et al (2015) and Michele, Sammarco & d'Errico (2016a) have extended the theory of Renzi & Dias (2013) to the case of a single and multiple arrays of neighbouring OWSCs with finite thickness in open sea and in front of a vertical breakwater.…”

Wave farm modelling of oscillating wave surge converters

“…A wave farm consisting of various layouts of a finite array of OWSCs is then studied considering complete hydrodynamic interaction among all the devices. The first theoretical model based on HIs was developed for an OWSC in a channel [13] and was then extended to study the hydrodynamics of an infinite array of WECs [14], a single device in the open ocean [15] and a finite array of inline converters [12]. Recently, the same method was also used to analyse the hydrodynamics of a flap-type device near a straight coast [16].…”