Weakly nonlinear theory for a gate-type curved array in waves. (25th June 2019)

• Record Type: Journal Article
• Authors: Michele, S.; Renzi, E.; Sammarco, P.
• Is Part Of: Journal of fluid mechanics. Volume 869(2019)
• Page Start: 238
• Page End: 263
• Publication Date: 2019-06-25
• Subjects: coastal engineering, -- wave–structure interactions; Fluid mechanics -- Periodicals; 532.005
• DOI: 10.1017/jfm.2019.223
• Languages: English
• ISSNs: 0022-1120

Abstract

Abstract : We analyse the effect of gate surface curvature on the nonlinear behaviour of an array of gates in a semi-infinite channel. Using a perturbation-harmonic expansion, we show the occurrence of new detuning and damping terms in the Ginzburg–Landau evolution equation, which are not present in the case of flat gates. Unlike the case of linearised theories, synchronous excitation of trapped modes is now possible because of interactions between the wave field and the curved boundaries at higher orders. Finally, we apply the theory to the case of surging wave energy converters (WECs) with curved geometry and show that the effects of nonlinear synchronous resonance are substantial for design purposes. Conversely, in the case of subharmonic resonance we show that the effects of surface curvature are not always beneficial as previously thought.