Abstract
A novel wave-energy device is presented. Both a preliminary proof-of-principle of a working, scaled laboratory version of the energy device is shown as well as the derivation and analysis of a comprehensive mathematical and numerical model of the new device. The wave-energy device includes a convergence in which the waves are amplified, a constrained wave buoy with a (curved) mast and direct energy conversion of the buoy motion into electrical power via an electro-magnetic generator. The device is designed for use in breakwaters and it is possible to be taken out of action during severe weather. The new design is a deconstruction of elements of existing wave-energy devices, such as the TapChan, IP wave-buoy and the Berkeley Wedge, put together in a different manner to enhance energy conversion and, hence, efficiency. The idea of wave-focusing in a contraction emerged from our work on creating and simulating rogue waves in crossing seas, including a "bore-soliton-splash". Such crossing seas have been recreated and modelled in the laboratory and in simulations by using a geometric channel convergence. The mathematical and numerical modelling is also novel. One monolithic variational principle governs the dynamics including the combined (potential-flow) hydrodynamics, the buoy motion and the power generation, to which the dissipative elements such as the electrical resistance of the circuits, coils and loads have been added a posteriori. The numerical model is a direct and consistent discretisation of this comprehensive variational principle. Preliminary numerical calculations are shown for the case of linearised dynamics; optimisation of efficiency is a target of future work.
Highlights
MOTIVATED by previous research on shallowwater and shallow-granular flows through contracting channels, and by water-wave impact against sea walls, a series of ad-hoc experiments have beenManuscript received 16 March; accepted 27 March; published 12 May, 2020
In the absence of the dissipative effects caused by the resistance of electrical circuits, induction coils and LED loads, the dynamics can be derived from a single variational principle (VP), detailed in Appendix A
Buoy motion and electro-magnetic currents are coupled through the connecting function G(Z) defined in (5), which appears in the equation (7f) for the vertical acceleration
Summary
MOTIVATED by previous research on shallowwater and shallow-granular flows through contracting channels, and by water-wave impact against sea walls, a series of ad-hoc experiments have been. Manuscript received 16 March; accepted 27 March; published 12 May, 2020. This article has been subject to single-blind peer review by a minimum of two reviewers. This is follow-up research that grew out of EPSRC grant EP/L025388/1 for O.
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