Application of the time-dependent mild-slope equations for the simulation of wake effects in the lee of a farm of Wave Dragon wave energy converters

Charlotte Beels, Peter A Troch, Kenneth De Visch, Jens Peter Kofoed, Griet De Backer

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

Time-dependent mild-slope equations have been extensively used to compute wave transformations near coastal and offshore structures for more than 20 years. Recently the wave absorption characteristics of a Wave Energy Converter (abbreviated as WEC) of the overtopping type have been implemented in a time-dependent mild-slope equation model by using numerical sponge layers. In this paper the developed WEC implementation is applied to a single Wave Dragon WEC and multiple Wave Dragon WECs. The Wave Dragon WEC is a floating offshore converter of the overtopping type. Two wave reflectors focus the incident wave power towards a ramp. The focussed waves run up the ramp and overtop in a water reservoir above mean sea level. The obtained potential energy is converted into electricity when the stored water drains back to the sea through hydro turbines. The wave reflectors and the main body (ramp and reservoir) are simulated as porous structures, exhibiting the same reflection, respectively absorption characteristics as obtained for the prototype Wave Dragon WEC. The wake effects behind a single Wave Dragon WEC are studied in detail for uni- and multidirectional waves. The shadow zone indicating the wake effect is decreasing with increasing directional spreading. The wake in the lee of a farm of five Wave Dragon WECs, installed in a staggered grid (3 WECs in the first row and 2 WECs in the second row), is calculated for three in-between distances of respectively D, 2D and 3D, with D the distance between the tips of the wave reflectors of a single WEC. As a result, a farm of five Wave Dragon WECs installed in a staggered grid with an in-between distance of 2D is preferred, when taking cost and spatial considerations into account.

Original languageEnglish (US)
Pages (from-to)1644-1661
Number of pages18
JournalRenewable Energy
Volume35
Issue number8
DOIs
StatePublished - Aug 2010
Externally publishedYes

Fingerprint

Farms
Wave power
Offshore structures
Sea level
Potential energy
Turbines
Electricity

Keywords

  • Farm
  • Mild-slope equations
  • Porous structure
  • Wake
  • Wave Dragon
  • Wave energy

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment

Cite this

Application of the time-dependent mild-slope equations for the simulation of wake effects in the lee of a farm of Wave Dragon wave energy converters. / Beels, Charlotte; Troch, Peter A; De Visch, Kenneth; Kofoed, Jens Peter; De Backer, Griet.

In: Renewable Energy, Vol. 35, No. 8, 08.2010, p. 1644-1661.

Research output: Contribution to journalArticle

Beels, Charlotte ; Troch, Peter A ; De Visch, Kenneth ; Kofoed, Jens Peter ; De Backer, Griet. / Application of the time-dependent mild-slope equations for the simulation of wake effects in the lee of a farm of Wave Dragon wave energy converters. In: Renewable Energy. 2010 ; Vol. 35, No. 8. pp. 1644-1661.
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