Methods for Boundary-Value Problems in Free-Surface Flows: The Third David W. Taylor Lecture, 27 August through 19 September 1974,

Wehausen, John V.

doi:10.21236/ada093352

Cited by 5 publications

(1 citation statement)

References 7 publications

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“…Also, pontoon-type floating bodies of relatively small dimensions find applications as coastal protection devices (floating breakwaters) and they are also frequently used as small boat marinas; see, e.g., [3][4][5][6][7]. In all these cases, the estimation of the wave-induced loads and motions of the floating structures can be based on the solution of the classical wave-body-seabed hydrodynamic-interaction problems; see, e.g., [8,9]. In particular, the performance of the Wave Energy Converters (WECs) operating in nearshore and coastal areas, characterized by variable bottom topography, is important for the estimation of the wave power absorption, determination of the operational characteristics of the system and could significantly contribute to the efficient design and layout of the WEC farms.…”

Section: Introductionmentioning

confidence: 99%

A Novel Method for Estimating Wave Energy Converter Performance in Variable Bathymetry Regions and Applications

2018

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A numerical model is presented for the estimation of Wave Energy Converter (WEC) performance in variable bathymetry regions, taking into account the interaction of the floating units with the bottom topography. The proposed method is based on a coupled-mode model for the propagation of the water waves over the general bottom topography, in combination with a Boundary Element Method for the treatment of the diffraction/radiation problems and the evaluation of the flow details on the local scale of the energy absorbers. An important feature of the present method is that it is free of mild bottom slope assumptions and restrictions and it is able to resolve the 3D wave field all over the water column, in variable bathymetry regions including the interactions of floating bodies of general shape. Numerical results are presented concerning the wave field and the power output of a single device in inhomogeneous environment, focusing on the effect of the shape of the floater. Extensions of the method to treat the WEC arrays in variable bathymetry regions are also presented and discussed.modes may have a significant impact on the wave phase evolution during propagation. Such a fact was demonstrated through the interference process in one-directional wave propagation as observed for either varying topographies (see e.g., [12,13]) or abrupt bathymetries including coastal structures (see e.g., [14][15][16]). For such problems, the consistent coupled-mode theory has been developed in [17], for the water waves propagation in variable bathymetry regions. Furthermore, it was subsequently extended for 3D bathymetry in [18], and applied successfully to treat the wave transformation over nearshore/coastal sites with steep 3D bottom features, like underwater canyons; see, e.g., [19,20].In recent works [21,22] the coupled-mode model is further extended to treat the wave-current-seabed interaction problem, with application to the wave scattering by non-homogeneous current over general bottom topography. The problem of the directional spectrum transformation of an incident wave system over a region of strongly varying three-dimensional bottom topography is further studied in [22]. The accuracy and efficiency of the coupled-mode method is tested, comparing numerical predictions against experimental data by [23] and calculations by the phase-averaged model SWAN [24,25]. Results are shown in various representative test cases demonstrating the importance of the first evanescent modes and the additional sloping-bottom mode when the bottom slope is not negligible.In this work, a methodology is presented to treat the propagation-diffraction-radiation problem locally around each WEC, supporting the calculation of the interaction effects of the floating units with variable bottom topography at a local scale. The method is based on the coupled-mode model developed by [17], and extended to 3D by [18], for water wave propagation over general bottom topography, in conjunction with the Boundary Element Method (BEM) for the hydrodynamic analysis of fl...

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Section: Introductionmentioning

confidence: 99%

A Novel Method for Estimating Wave Energy Converter Performance in Variable Bathymetry Regions and Applications

2018

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An expansion theorem for water-wave potentials

Athanassoulis

1984

J Eng Math

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Consider an infinitely long, horizontal cylinder of arbitrary cross section, floating on the free surface of an inviscid, incompressible fluid of infinite depth. The fluid motion is assumed two-dimensional, irrotational and of small amplitude, and it is described by a wave potential satisfying the Laplace equation, the usual linearized free-surface and body-boundary conditions, as well as proper conditions at infinity. A general multipole expansion for the wave potential is derived, converging throughout the fluid domain. Conditions are also stated under which the corresponding expansion for the fluid velocity converges up to and on the body boundary. In this case the multipole expansion may be used in the numerical solution or in the theoretical study of various water-wave problems.To obtain the expansion, a decomposition of the wave potential in a regular wave, a wave source, a wave dipole and a regular wave-free part is first invoked. Subsequently, using Texeira's series and the conformal mapping between the semicircular region I~1 >~ 1, Im ~" ~< 0, and the fluid domain, it is shown that the regular part of the wave potential can be represented by a convergent series of wave-free multipoles, which are given explicitly in terms of the mapping function.

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Measurements of two- and three-dimensional waves in a channel, including the vicinity of cut-off frequencies

Shemer

Kit

Miloh

1986

Experiments in Fluids

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Methods for Boundary-Value Problems in Free-Surface Flows: The Third David W. Taylor Lecture, 27 August through 19 September 1974,

Cited by 5 publications

References 7 publications

A Novel Method for Estimating Wave Energy Converter Performance in Variable Bathymetry Regions and Applications

A Novel Method for Estimating Wave Energy Converter Performance in Variable Bathymetry Regions and Applications

An expansion theorem for water-wave potentials

Measurements of two- and three-dimensional waves in a channel, including the vicinity of cut-off frequencies

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