Journal ArticleDOI
Wave generation by an oscillating surface-pressure and its application in wave-energy extraction
TLDR
In this paper, a two-dimensional analysis based on linear surface-wave theory is developed for an oscillating-water-column wave-energy device in water of arbitrary constant depth, and the results show that air compressibility can be important in practice, and its effects may in general be satisfactorily represented by linearization.Abstract:
A two-dimensional analysis, based on linear surface-wave theory, is developed for an oscillating-water-column wave-energy device in water of arbitrary constant depth. The immersed part of the structure is assumed of shallow draught except for a submerged vertical reflecting wall. Both the cases of linear and nonlinear power take-off are considered. The results show that air compressibility can be important in practice, and its effects may in general be satisfactorily represented by linearization. The analysis indicates that using a turbine whose characteristic exhibits a phase difference between pressure and flow rate may be a method of strongly reducing the chamber length and turbine size with little change in the capability of energy extraction from regular waves. It was found in two examples of devices with strongly nonlinear power take-off that the maximum efficiency is only marginally inferior to what can be achieved in the linear case.read more
Citations
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Journal ArticleDOI
Semi-analytical study on an integrated-system with separated heaving OWC and breakwater: Structure size optimization and gap resonance utilization
TL;DR: In this article , a novel integrated system composed of an offshore heaving OWC device and a floating stationary breakwater with a certain length of gap between each other is proposed under the framework of potential flow theory, corresponding theoretical model is established and solved by decomposing the boundary-value problems into one wave scattering component and two radiation components.
Journal ArticleDOI
Energy extraction from the motion of an oscillating water column
Hao Wang,Jeffrey Falzarano +1 more
TL;DR: In this paper, the authors used potential theory and Galerkin methods to solve the fluid motion inside an oscillating water column (OWC) for energy extraction from a regular wave.
Journal ArticleDOI
Performance of a Shore Fixed Oscillating Water Column Device for Different Bottom Slopes and Front Wall Drafts: A Study Based on Computational Fluid Dynamics and BIEM
TL;DR: In this paper, the hydrodynamic performance of a shore-fixed OWC device for different bottom slopes using two numerical approaches, namely, computational fluid dynamics (CFD) and boundary integral equation method (BIEM), is investigated.
Journal ArticleDOI
Two-phase flow simulations of fixed 3D oscillating water columns using OpenFOAM: A comparison of two methods for modeling quadratic power takeoff
Zhenhua Huang,Shijie Huang +1 more
TL;DR: In this paper, the authors examined the performance of a numerical method that introduces an artificial sink term to the Reynolds-averaged Navier Stokes equations to simulate the flow through an orifice used as a quadratic Power Takeoff (PTO) for oscillating water columns (OWCs).
Journal ArticleDOI
CFD analysis of the energy conversion process in a fixed oscillating water column (OWC) device with a Wells turbine
TL;DR: In this article, a numerical analysis of the fluid dynamic interaction between waves and a U-shaped OWC breakwater, focusing on the energy conversion process, was carried out to analyze the performance of the plant and analyze the resonance with incoming waves.
References
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Surface Waves
TL;DR: In this paper, the evanescent field structure over the wave front, as represented by equiphase planes, is identified as one of the most important and easily recognizable forms of surface wave.
Journal ArticleDOI
Wave-power absorption by systems of oscillating surface pressure distributions
TL;DR: In this article, the efficiency of energy absorption of a system of uniform oscillatory surface pressure distributions was derived based on linear water-wave theory and the results showed the close analogies which exist with theories for absorbing oscillatory rigid bodies and a number of new reciprocal relations for pressure distributions.
Journal ArticleDOI
On the Theory of the Wells Turbine
Luís M.C. Gato,A.F. de O. Falcão +1 more
TL;DR: In this article, the authors present an etude theorique du comportement thermodynamique de la turbine de Wells, a turbine a ecoulement axial adaptee a l'extraction d'energie a partir d'un energy alternatif, and obtention d'expressions for la forme d'ailette rendant maximal le rendement of the turbine.
Book ChapterDOI
Computer oriented algorithms for solving systems of simultaneous nonlinear algebraic equations
TL;DR: In this paper, the authors discuss the problem of solving N real equations in N real unknowns, and present the best algorithms for the various facets of the given system, such as getting into a region of local convergence from poor initial estimates, achieving guaranteed convergence to a root from anywhere within a specified region by suitably restricting the functions fi, using a technique in a vicinity of a root (local technique) which is fast, stable and which does not require the user to furnish derivatives of the function fi; and finally, obtaining additional roots of a nonlinear system without converging again to
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