Optimization of Spacing for Oscillating Wave Surge Converter Arrays Using Genetic Algorithm
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 143, Issue 2
Abstract
The oscillating wave surge converter (OWSC) is a type of ocean wave power device typically consisting of a flap, or arm, hinged at the bottom to allow forward and backward movement by surging waves, and is efficient in generating electricity from waves due to its capability in operating at a wide range of wave spectra. The power generated from the OWSC could be further maximized by arranging the devices in an array at their optimal spacing. This paper addresses the optimization of device configuration within an array by using the genetic algorithm (GA) scheme, for which the spacings between devices are taken as the optimization variables, and the maximum q-factor is chosen as the objective function. The q-factor is a performance assessment parameter that quantifies the average total power produced by an array compared to an individual device. Three array layouts—namely, the single-, double-, and triple-array, each comprising 12 OWSCs—were considered. The pitch response amplitude operator (RAO) of each device in the array was evaluated, from which the power generated and q-factor were determined. The influence of different wave periods and their propagation directions on the array optimal spacing and q-factor was investigated. This study shows that the optimal spacing is highly correlated to the scattering parameter. The results presented here will aid engineers in selecting appropriate spacing that would maximize the power production. The results also provide an enhanced understanding of the performance of the OWSC array when arranged in different configurations.
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Acknowledgments
The authors are grateful for the financial support of the U.K. Engineering and Physical Sciences Research Council (EPSRC) through the EcoWatt2050 Research Consortium (EPSRC reference: EP/K012851/1).
References
Aquamarine Power. (2012). “Project: North-west Lewis.” 〈http://www.aquamarinepower.com/projects/north-west-lewis/〉.
Babarit, A. (2010). “Impact of long separating distances on the energy production of two interacting wave energy converters.” Ocean Eng., 37(8), 718–729.
Babarit, A., and Hals, J. (2011). “On the maximum and actual capture width ratio of wave energy converters.” Proc., 10th European Wave Energy Conf., University of Southampton Sustainable Energy Research Group, Southampton, U.K.
Bean, J. C. (1994). “Genetic algorithms and random keys for sequencing and optimization.” ORSA J. Comput., 6(2), 154–160.
Borgarino, B., Babarit, A., and Ferrant, P. (2012). “Impact of wave interactions effects on energy absorption in large arrays of wave energy converters.” Ocean Eng., 41, 79–88.
Budal, K. (1977). “Theory for absorption of wave power by a system of interacting bodies.” J. Ship Res., 21(4), 248–253.
Carbon Trust. (2006). Future marine energy, result of marine energy challenge: Cost competitiveness and growth of wave and tidal stream energy, London.
Chakrabarti, S. K. (1987). Hydrodynamics of offshore structures, WIT Press, Southampton, U.K.
Child, B., and Venugopal, V. (2010). “Optimal configurations of wave energy device arrays.” Ocean Eng., 37(16), 1402–1417.
Cruz, J., Sykes, R., Siddorn, P., and Taylor, R. E. (2010). “Estimating the loads and energy yield of arrays of wave energy converters under realistic seas.” IET Renewable Power Gener., 4(6), 488–497.
Davis, L. (1991). Handbook of genetic algorithms, Van Nostrand Reinhold, New York.
De Backer, G. (2009). “Hydrodynamic design optimization of wave energy converters consisting of heaving point absorbers.” Ph.D., Ghent Univ., Gent, Belgium.
Delauré, Y. M. C., and Lewis, A. (2003). “3D hydrodynamic modelling of fixed oscillating water column wave power plant by a boundary element methods.” Ocean Eng., 30(3), 309–330.
Falnes, J. (2002). Ocean waves and oscillating systems, Cambridge Univ. Press, Cambridge, U.K.
Faltinsen, O. M. (1993). Sea loads on ships and offshore structures, Cambridge Univ. Press, Cambridge, U.K.
Goldberg, D. E., and Deb, K. (1991). “A comparative analysis of selection schemes used in genetic algorithms.” Found. Genet. Algorithms, 1, 69–93.
MATLAB [Computer software]. MathWorks, Natick, MA.
Newman, J. N. (1977). Marine hydrodynamics, MIT Press, Cambridge, MA.
Newman, J. N. (1985). “Algorithms for the free-surface Green function.” J. Eng. Math., 19(1), 57–67.
O'Hara Murray, R. (2015). “Tidal stream and wave energy array scenarios for the Pentland Firth and Orkney Waters strategic area.” TeraWatt position papers: A toolbox of methods to better understand and assess the effects of tidal and wave energy arrays on the marine environment, Marine Alliance for Science and Technology for Scotland, Fife, Scotland, 31–47.
Renzi, E., and Dias, F. (2013). “Wave-power extraction from a finite array of oscillating wave surge converters.” Proc., Int. Workshop on Water Waves and Floating Bodies, Ücole Centrale de Marseille, Marseille, France, IWWWFB28_48.
Renzi, E., Doherty, K., Henry, A., and Dias, F. (2014). “How does Oyster work? The simple interpretation of Oyster mathematics.” Eur. J. Mech. B. Fluids, 47, 124–131.
Sarkar, D., Renzi, E., and Dias, F. (2014). “Interactions between an oscillating wave surge converter and a heaving wave energy converter.” J. Ocean Wind Energy, 1(3), 135–142.
Tay, Z. Y., Wang, C. M., and Utsunomiya, T. (2009). “Hydroelastic responses and interactions of floating fuel storage modules placed side-by-side with floating breakwaters.” Marine Struct., 22(3), 633–658.
Vantorre, M., Banasiak, R., and Verhoeven, R. (2004). “Modelling of hydraulic performance and wave energy extraction by a point absorber in heave.” Appl. Ocean Res., 26(1), 61–72.
WAMIT 7.0 [Computer software]. Wamit Inc., Chestnut Hill, MA.
WAMIT, Inc. (2011). “Wamit user manual.” Version 7.0, Chestnut Hill, MA.
Wang, C. M., and Tay, Z. Y. (2010). “Hydroelastic analysis and response of pontoon-type very large floating structures.” Fluid structure interaction II, H.-J., Bungartz, M., Mehl, and M., Schäfer, eds., Springer-Verlag, Berlin, pp. 103–130.
WaveNet. (2003). “Final report of the European thematic network on wave energy.” Energy Environment and Sustainable Development Programme, Brussels, Belgium.
Williams, A. N., and Abul-Azm, A. G. (1989). “Hydrodynamic interactions in floating cylinder arrays—II. Wave radiation.” Ocean Eng., 16(3), 217–263.
Wolgamot, H. A., Taylor, P. H., and Eatock Taylor, R. (2012). “The interaction factor and directionality in wave energy arrays.” Ocean Eng., 47, 65–73.
Xodus Group. (2011). “Brough head wave farm—Scoping report.” Xodus Group, Aberdeen, U.K.
Information & Authors
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Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 143 • Issue 2 • March 2017
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Jan 19, 2016
Accepted: Jul 19, 2016
Published online: Sep 27, 2016
Discussion open until: Feb 27, 2017
Published in print: Mar 1, 2017
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