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
Efficient determination of nonlinear response of an array of Oscillating Water Column energy harvesters exposed to random sea waves
Giovanni Malara,Pol D. Spanos +1 more
TL;DR: In this article, an approximate solution scheme based on the concept of statistical linearization is developed for estimating the response of an array of Oscillating Water Columns (OWCs) installed in a vertical breakwater and exposed to the action of random waves.
Journal ArticleDOI
Determination of damping coefficient experimentally and mathematical vibration modelling of OWC surface fluctuations
TL;DR: In this paper, a mathematical vibration model is developed to estimate the water surface average fluctuations in the chamber and the related phase angles, and a particular relative opening height of the chamber is revealed that provides minimum damping which in turn maximizes the highest average chamber water surface fluctuation value regardless of the incident wave parameters.
Journal ArticleDOI
A novel dual-chamber oscillating water column system with dual lip-wall pitching motions for wave energy conversion
TL;DR: In this article , a dual-chamber Oscillating water column (OWC) system with pitching front and mid lip-walls is proposed to improve energy extraction within a wider wave frequency regime.
Journal ArticleDOI
A novel concept for reducing wave reflection from OWC structures with application of harbor agitation mitigation/coastal protection: theoretical investigations
TL;DR: In this paper, the authors presented a theoretical study on the hydrodynamic performance of a novel coastal structure, which combines a conventional harbor/coast-based single-chamber OWC device and a surface-piercing perforated barrier.
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
Related Papers (5)
Hydrodynamic characteristics of an oscillating water column device
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