Abstract

We consider a flap gate farm, i.e. a series of P arrays, each made of Q neighbouring flap gates, in an open sea of constant depth, forced by monochromatic incident waves. The effect of the gate thickness on the dynamics of the system is taken into account. By means of Green's theorem a system of hypersingular integral equations for the velocity potential in the fluid domain is solved in terms of Legendre polynomials. We show that synchronous excitation of the natural frequencies of Sammarco et al. (2013) yields large amplitude response of gate motion. This aspect is fundamental for the optimisation of the gate farm for energy production.

Highlights

  • The flap gate systems, i.e. one or more floating bodies hinged at the bottom of the sea and rolling under incoming waves, have recently proved very effective to extract energy from the sea (Whittaker et al [1])

  • We consider a flap gate farm, i.e. a series of P arrays, each made of Q neighbouring flap gates, in an open sea of constant depth, forced by monochromatic incident waves

  • In order to evaluate the effects of the finite gate thickness 2b, the simplest case of P = Q = 1, i.e. the case of one gate in the open sea is considered

Read more

Summary

Introduction

The flap gate systems, i.e. one or more floating bodies hinged at the bottom of the sea and rolling under incoming waves, have recently proved very effective to extract energy from the sea (Whittaker et al [1]). For one array of gates spanning the entire width of a channel, experiments showed that the gates can be excited to oscillate at half the incident wave frequency with a very large amplitude (Mei et al [2]). Li and Mei [5] found the (Q − 1) eigenfrequencies of one array made by Q identical gates spanning the full width of a channel. Large amplitude motions of the gates occur when the incident wave frequency approaches the eigenfrequencies. Monochromatic plane normal incidence waves of amplitude A, period T and angular frequency ω = 2 /T, coming from x =+ ∞, force the gates to oscillate back and forth. Note that the no flux condition (6) is given on the finite edges of each array facing the open sea, without channel walls.

Semi-analytical solution
Gate dynamics
Eigenfrequencies and eigenvectors
The radiation potential in the far field
The Haskind–Hanaoka relation for the gate farm
One gate in the open sea: the effects of the gate thickness
The influence of the power take-off on the capture width
Conclusions
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.