Elsevier

Applied Ocean Research

Volume 43, October 2013, Pages 68-70
Applied Ocean Research

Technical note
Maximum wave power absorption by flexible line attenuators

https://doi.org/10.1016/j.apor.2013.08.003Get rights and content

Highlights

  • Published theory for maximum wave power absorption width of flexible line attenuators was clarified.

  • Example of wave-like body deformation was explicitly treated.

  • Case equivalent to optimal combination of cosine and sine modes for wavelengths smaller than about one and a half the body length.

  • Case equivalent to cosine mode for very long wavelengths.

Abstract

The general applicability of Newman's groundbreaking work on wave power absorption (Newman, 1976 [1]; Newman, 1979 [2]; Mei and Newman1979 [3]) is unambiguously demonstrated in the practical case of a slender body undergoing wave-like deformations in head seas.

Section snippets

Background

In 1976, Newman published a seminal hydrodynamic study where the last section is dedicated to wave energy extraction [1]. Based on this work, the maximum wave power absorption characteristics of slender flexible rafts (line attenuators) in head seas were theoretically determined [2,3]. Shortly thereafter, Farley analyzed and experimentally tested such a device subject to wavelike deformations focused in the forward direction (along the incident wave) [4]. Some theoretical evidence that this

Discussion

Consider an incident linear wave of amplitude A, circular frequency ω and wavenumber k traveling forward along the x-axis over deep water. Note that the time-dependence exp(−iωt) is chosen here. For a stationary wave power converter subject to vertical displacements of the form Anvnfn, where vn is the non-dimensional complex displacement amplitude for mode fn, the following expression for the absorption width was derived [2]:W=2nvnHn*(π)k2π02πnvnHn(θ)2dθ

The Kochin function Hn is defined

References (7)

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Cited by (1)

  • Maximum wave power absorption by slender bodies of arbitrary cross sections in oblique seas

    2014, Applied Ocean Research
    Citation Excerpt :

    In Section 5, results are presented for the forward wavelike deformations of a flexible slender body. Such systems, undergoing vertical motions in head seas, have been studied before [8–10]. Next, the more practical case of a two-hinge articulated raft unrestrained in heave and pitch is considered, as in Newman [5].

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