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Journal ArticleDOI

A second-order theory for an array of curved wave energy converters in open sea

01 Jul 2019-Journal of Fluids and Structures (Elsevier)-Vol. 88, pp 315-330
TL;DR: A second-order nonlinear theory for an array of curved flap-type wave energy converters (WECs) in open sea, excited by oblique incident waves is presented in this paper.
About: This article is published in Journal of Fluids and Structures.The article was published on 2019-07-01 and is currently open access. It has received 22 citations till now. The article focuses on the topics: Mathieu function & Velocity potential.
Citations
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Journal ArticleDOI
TL;DR: In this article, the authors focus on the most suitable form of hydrodynamic modeling for the next generation wave energy converter (WEC) design tools, focusing on what CFD theories exist intermediate to LPF and RANS as well as other modeling options that are computationally fast while retaining higher fidelity than LPF.
Abstract: This review focuses on the most suitable form of hydrodynamic modeling for the next generation wave energy converter (WEC) design tools. To design and optimize a WEC, it is estimated that several million hours of operation must be simulated, perhaps one million hours of WEC simulation per year of the R&D program. This level of coverage is possible with linear potential flow (LPF) models, but the fidelity of the physics included is not adequate. Conversely, while Reynolds averaged Navier–Stokes (RANS) type computational fluid dynamics (CFD) solvers provide a high fidelity representation of the physics, the increased computational burden of these models renders the required amount of simulations infeasible. To scope the fast, high fidelity options, the present literature review aims to focus on what CFD theories exist intermediate to LPF and RANS as well as other modeling options that are computationally fast while retaining higher fidelity than LPF.

75 citations


Cites background from "A second-order theory for an array ..."

  • ...[175] 2nd Order PF Curved OSC array Nonlinear effects of the curved surface...

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  • ...[175–177] then consider an array of the curved gate-type WECs, in a channel [176,177] and in the open sea [175], showing constructive interactions, in terms of generated power, that are not possible for linearized theories or flat WECs....

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Journal ArticleDOI
TL;DR: In this paper, a mathematical model is developed to analyze the hydrodynamics of a novel oscillating water column (OWC) in a hybrid wind-wave energy system, which has a coaxial cylindrical structure in which the internal cylinder represents the mono-pile of an offshore wind turbine while the external cylinder has a skirt whose scope is to guide the wave energy flux inside the chamber.

45 citations

Journal ArticleDOI
TL;DR: A novel analytical wake model of OWSC is proposed and it is demonstrated that staggered layouts with narrow and wide OWSCs placed in the front and back of wave energy farms, respectively, were economical and appropriate.

17 citations

Journal ArticleDOI
24 Nov 2020-Energies
TL;DR: In this article, the authors present a mathematical model to investigate the extraction of wave power by flexible floaters, based on the method of dry modes, coupled with a matched eigenfunction expansion.
Abstract: We present a novel mathematical model to investigate the extraction of wave power by flexible floaters. The model is based on the method of dry modes, coupled with a matched eigenfunction expansion. Our model results compare satisfactorily with preliminary data obtained from a demonstrator device, developed at the University of Groningen. We show that the role of elasticity is to increase the number of resonant frequencies with respect to a rigid body, which has a positive effect on wave power output. The mathematical model is then extended to irregular incident waves, described by a JONSWAP spectrum. Our results show that the peak capture factors decrease in irregular waves, as compared to the monochromatic case. However, the system becomes more efficient at non-resonant frequencies. This work highlights the need to scale-up experimental investigations on flexible wave energy converters, which are still a small minority, compared to those on rigid converters.

14 citations

Journal ArticleDOI
TL;DR: In this paper, an analytical model for the evolution of hydroacoustic waves in weakly compressible fluids characterised by depth variations of the sound speed profile is presented. But this model does not take into account the vertical variation of sound speed.
Abstract: We present a novel analytical model for the evolution of hydroacoustic waves in weakly compressible fluids characterised by depth variations of the sound speed profile. Using a perturbation expansion in terms of the small vertical variation of the sound speed, we derive a novel expression for the second-order velocity potential and show that this solution does not exist in the case of homogeneous sound speed. At the third order, we derive a linear Schr¨odinger equation governing the evolution of the wave envelope for large length and time scales, which features new terms depending on the sound speed distribution. We show that for generalised sound speed vertical profiles the frequency of the hydroacoustic signal can increase or decrease with respect to the constant sound speed case, depending on the profile. This has substantial implications on the speed of the wavetrain envelope. Our findings suggest the need to extend existing models that neglect the sound speed vertical variation, especially in view of applications to tsunami early warning.

13 citations

References
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Book
01 Jan 1964

2,100 citations

Book
01 Jan 1977
TL;DR: In this article, a new edition has been expanded to contain an introduction to areas of current importance such as bifurcation, structural stability, and chaotic behavior, including linearization, perturbation theory, subharmonics, stability and limit cycles.
Abstract: This new edition has been expanded to contain an introduction to areas of current importance such as bifurcation, structural stability and chaotic behavior Other topics include linearization, perturbation theory, subharmonics, stability, the existence of limit cycles, and Poincare maps The text is concerned with practical applications and includes over 400 examples and exercises"

1,566 citations


"A second-order theory for an array ..." refers background or methods in this paper

  • ...A nonlinear set of governing 49 equations is derived and decomposed in a sequence of linearised boundary 50 value problems through the use of a standard perturbation-harmonic expan51 sion technique (Jordan and Smith, 2011)....

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  • ...The combination of harmonic forcing terms at higher orders implies that the 156 response of the array includes several harmonics (Jordan and Smith, 2011)....

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Journal ArticleDOI
TL;DR: In this article, the mean annual power absorption of a selection of eight Wave Energy Converters (WECs) with different working principles is derived based on numerical modeling. But, despite very different working principle and dimensions, power performance of the selected devices vary much less than the average power absorption.

578 citations

Book
01 Jan 1981

364 citations

Journal ArticleDOI
Bernard Molin1
TL;DR: In this paper, a non-linear theory is presented to derive second-order waveloads, in terms of the wave-steepness, which makes the solution valid for all range of wave frequencies.

223 citations


"A second-order theory for an array ..." refers background in this paper

  • ...Analytical models concerning cylindrical structures involved several authors in the past (Molin, 1979; Chau and Eatock Taylor, 1992; Kim and Yue, 1989; Newman, 1996), while the second-order diffraction theory for elliptical cylinders has more recently been developed by Chatjigeorgiou and Mavrakos…...

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  • ...Analytical models concerning cylindrical structures involved several authors in the past (Molin, 1979; Chau and Eatock Taylor, 1992; Kim and Yue, 1989; Newman, 1996), while the second-order diffraction theory for elliptical cylinders has more recently been developed by Chatjigeorgiou and Mavrakos (2012)....

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