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
Modelling, simulation and testing of a submerged oscillating water column
TL;DR: In this paper, the authors presented the development of a time-domain simulation model, with experimental verification, for a submerged oscillating water column (OWC) for a Stellenbosch Wave Energy Converter (SWEC).
Journal Article
Devices for sea wave power extraction to electrical energy conversion
TL;DR: In this paper, the authors describe several devices used presently to extract mechanical energy from the waves and their advantages and disadvantages are presented as conclusions, in particular the modern Pelamis system is described in some detail.
Journal ArticleDOI
Symmetry-Breaking for Airflow Control Optimization of an Oscillating-Water-Column System
TL;DR: The present article deals with the airflow control optimization problem in an oscillating-water-column using the Particle Swarm Optimization (PSO), and shows that shrinking the search space helped to reduce the search time and ameliorate the efficiency of the PSO algorithm.
Dissipation in oscillating water columns
TL;DR: In this article, an extensive study of the internal fluid dynamics of an oscillating water column (OWC) is carried out to identify those damping factors, and furthermore, to estimate the amount of energy loss due to their presence in OWCs.
Journal ArticleDOI
Long waves absorption by a dual purpose Helmholtz-resonance OWC breakwater
TL;DR: In this paper , a hybrid breakwater-WEC system consisting of a Helmholtz resonance oscillating water column (OWC) caisson array and a perforated wall is proposed to attenuate long 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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