scholarly journals Moment of Wave Energy Model in Water of Finite Depth

2020 ◽  
Vol 8 (5) ◽  
pp. 2781-2785

In this work, we have considered a particular wave energy device to create electrical energy in water. The device contains a submerged cylindrical obstacle placed above a plate which is also assumed as a cylindrical structure. Also the diffracted potentials are derived by applying several mathematical models for each region of the fluid. Due to continuous flow of the fluid, we have introduced a system of equation for some unknown constants which are involved in potentials expression. Finally, we derived moment of the device due to diffraction wave field and present graphically.

In this work, we have consider a particular wave energy device to create electrical energy in water. The device contains a submerged cylindrical obstacle placed above a plate which is also assume as a cylindrical structure. Also the diffracted potentials are derived by applying several mathematical model for each region of the fluid. Due to continuous flow of the fluid, we have introduce a system of equation for some unknown constants which are involve in potentials expression. Finally, we derived moment of the device due to diffraction wave field and present graphically.


Water Waves ◽  
2019 ◽  
Vol 1 (2) ◽  
pp. 217-258
Author(s):  
O. Bokhove ◽  
A. Kalogirou ◽  
W. Zweers

AbstractWe explore extreme nonlinear water-wave amplification in a contraction or, analogously, wave amplification in crossing seas. The latter case can lead to extreme or rogue-wave formation at sea. First, amplification of a solitary-water-wave compound running into a contraction is disseminated experimentally in a wave tank. Maximum amplification in our bore–soliton–splash observed is circa tenfold. Subsequently, we summarise some nonlinear and numerical modelling approaches, validated for amplifying, contracting waves. These amplification phenomena observed have led us to develop a novel wave-energy device with wave amplification in a contraction used to enhance wave-activated buoy motion and magnetically induced energy generation. An experimental proof-of-principle shows that our wave-energy device works. Most importantly, we develop a novel wave-to-wire mathematical model of the combined wave hydrodynamics, wave-activated buoy motion and electric power generation by magnetic induction, from first principles, satisfying one grand variational principle in its conservative limit. Wave and buoy dynamics are coupled via a Lagrange multiplier, which boundary value at the waterline is in a subtle way solved explicitly by imposing incompressibility in a weak sense. Dissipative features, such as electrical wire resistance and nonlinear LED loads, are added a posteriori. New is also the intricate and compatible finite-element space–time discretisation of the linearised dynamics, guaranteeing numerical stability and the correct energy transfer between the three subsystems. Preliminary simulations of our simplified and linearised wave-energy model are encouraging and involve a first study of the resonant behaviour and parameter dependence of the device.


1984 ◽  
Vol 144 ◽  
pp. 419-443 ◽  
Author(s):  
A. G. Davies ◽  
A. D. Heathershaw

Surface waves travelling in water of finite depth may be scattered by a region of undulating bottom topography. The present study is concerned with the idealized two-dimensional situation in which long-crested surface waves are incident upon a patch of long-crested regular bottom ripples. The principal question examined concerns the amount of incident wave energy that is reflected by the ripple patch. Linear perturbation theory is used to show that the reflection coefficient is both oscillatory in the quotient of the length of the patch and the surface wavelength, and also strongly dependent upon the quotient of the surface and bed wavelengths. In particular, there is a Bragg resonance between the surface waves and the ripples, which is associated with the reflection of incident wave energy. A secondary question concerns the nature of the wave field in the immediate vicinity of the ripple patch. In resonant cases, it is shown how the partially standing wave on the upwave side of the ripple patch gives way, in an almost linear manner over the patch itself, to a progressive transmitted wave on the downwave side. The theoretical predictions are compared with an extensive set of laboratory observations made in a wave tank. Comparisons relating both to the reflection coefficient, and also to the wave field over the ripple patch, are shown to give consistently good agreement. Finally, the implications of the results for sediment transport on an erodible bed are examined.


2021 ◽  
Vol 13 (11) ◽  
pp. 2070
Author(s):  
Ana Basañez ◽  
Vicente Pérez-Muñuzuri

Wave energy resource assessment is crucial for the development of the marine renewable industry. High-frequency radars (HF radars) have been demonstrated to be a useful wave measuring tool. Therefore, in this work, we evaluated the accuracy of two CODAR Seasonde HF radars for describing the wave energy resource of two offshore areas in the west Galician coast, Spain (Vilán and Silleiro capes). The resulting wave characterization was used to estimate the electricity production of two wave energy converters. Results were validated against wave data from two buoys and two numerical models (SIMAR, (Marine Simulation) and WaveWatch III). The statistical validation revealed that the radar of Silleiro cape significantly overestimates the wave power, mainly due to a large overestimation of the wave energy period. The effect of the radars’ data loss during low wave energy periods on the mean wave energy is partially compensated with the overestimation of wave height and energy period. The theoretical electrical energy production of the wave energy converters was also affected by these differences. Energy period estimation was found to be highly conditioned to the unimodal interpretation of the wave spectrum, and it is expected that new releases of the radar software will be able to characterize different sea states independently.


2013 ◽  
Vol 3-4 ◽  
pp. e26-e39 ◽  
Author(s):  
J. Cameron McNatt ◽  
Vengatesan Venugopal ◽  
David Forehand

Author(s):  
Tsunehiro SEKIMOTO ◽  
Sayaka NAKAJIMA ◽  
Hiroyuki KATAYAMA ◽  
Kenya TAKAHASHI

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