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
Experimental and numerical measurements of wave forces on a 3D offshore stationary OWC wave energy converter
TL;DR: In this article, the wave forces on a 1:50 model-scale of an offshore stationary Oscillating Water Column (OWC) device are studied in 3D physical and numerical wave tanks.
Journal ArticleDOI
Fundamental formulae for wave-energy conversion.
Johannes Falnes,Adi Kurniawan +1 more
TL;DR: New formulae are derived that relate the ‘added-mass’ matrix, as well as a couple of additional reactive radiation-parameter matrices, to the difference between kinetic energy and potential energy in the water surrounding the immersed oscillating WEC array.
Journal ArticleDOI
Air turbine optimization for a bottom-standing oscillating-water-column wave energy converter
TL;DR: In this paper, a case study was selected to investigate these issues: the existing bottom-standing plant on the shoreline of the island of Pico, in Azores Archipelago.
Journal ArticleDOI
CFD modelling of a small–scale fixed multi–chamber OWC device
TL;DR: In this paper, an incompressible three-dimensional CFD model is constructed to simulate a fixed Multi-Chamber OWC (MC-OWC) device and validated; the simulation results are found to be in good agreement with experimental results obtained from a scale physical model tested in a wave tank.
Journal ArticleDOI
Characteristics of orifices for modeling nonlinear power take-off in wave-flume tests of oscillating water column devices
Fang He,Zhenhua Huang +1 more
TL;DR: In this paper, a series of wave-flume experiments was conducted to examine the hydrodynamic performance of a rectangular OWC device fixed in regular waves, and two types of orifices were used to simulate the nonlinear power take-off (PTO) mechanism, and the effects of orifice geometry were examined.
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
D. V. Evans,Richard Porter +1 more