Skip to main content
    • Aa
    • Aa

Wave power extraction from an oscillating water column at the tip of a breakwater


To reduce the costs of construction, operation, maintenance, energy storage and grid connection, some devices for extracting energy from sea waves are likely to be installed on the coast. We study theoretically a single oscillating water column (OWC) installed at the tip of a long and thin breakwater. The linearized problems of radiation and scattering for a hollow cylinder with an open bottom are then solved by the usual method of eigenfunction expansions and integral equations. Since a thin breakwater is the limit of a wedge, an exact solution for the diffraction by a solid cylinder at the tip of a wedge is derived to facilitate the analysis. Following Sarmento & Falcão (J. Fluid Mech., vol. 150, 1985, pp. 467–485), power takeoff by Wells turbines is modelled by including air compressibility in the chamber above the water surface. The effects of air compressibility on the extraction efficiency is studied. It is shown that for this simple geometry the angle of incidence affects the waves outside the structure but not the extracted power.

Corresponding author
Email address for correspondence:
Hide All
Budal K. & Falnes J. 1977 Optimum operation of improved wave-power converter. Marine Sci. Comm. 3, 133150.
Erdélyi A., Magnus W. Oberhettinger F. & Tricomi F. G. 1954 Tables of Integral Transforms 1.10. McGraw-Hill.
Evans D. V. 1976 A theory for wave power absorption by oscillating bodies. J. Fluid Mech. 77, 125.
Evans D. V. 1978 The oscillating water column wave energy device. J. Inst. Math. Appl. 22, 423433.
Evans D. V. 1981 Power from water waves. Annu. Rev. Fluid Mech. 13, 157187.
Evans D. V. 1982 Wave-power absorption by systems of oscillating surface pressure distributions. J. Fluid Mech. 114, 481–99.
Evans D. V. 1988 The maximum efficiency of wave-energy devices near coast lines. Appl. Ocean Res. 10, 162164.
Evans D. V. & Porter R. 1995 Hydrodynamics characteristics of an oscillating water column device. Appl. Ocean Res. 17, 155164.
Evans D. V. & Porter R. 1997 Efficient calculation of hydrodynamic properties of OWC-type devices. J. Offshore Mech. Arctic Engng 119, 210218.
Falcão A. F. de O. 2000 The shoreline OWC power plant at the azores. In Fourth European Wave Energy Conf., Aalborg, Denmark.
Falcão A. F. de O. 2002 Control of an oscillating-water-column wave power plant for maximum energy production. Appl. Ocean Res. 24, 5971.
Falcão A. F. de O. & Sarmento A. J. N. A. 1982 Wave generation by a periodic surface pressure and its application in wave-energy extraction. In Fifteenth Intl Cong. on Theor. Appl. Mech., Toronto, Canada.
Falnes J. 2002 Ocean Waves and Oscillating Systems. Cambridge University Press.
Garrett C. J. R. 1970 Bottomless harbours. J. Fluid Mech. 43, 433449.
Heath T. V. 2007 The development of a turbo-generation system for application in an OWC breakwater. In Seventh European Wave and Tidal Energy Conf., Porto, Portugal.
Martins E., Siveira Ramos F., Carrilho L., Justino P., Gato L., Trigo L. & Neumann F. 2005 Ceodouro project: overall design of an OWC in the new Oporto breakwater. In Sixth European Wave and Tidal Energy Conf., Glasgow, UK.
Martins-Rivas H. & Mei C. C. 2007 Diffraction effects near Foz do Douro breakwater. In Proc. oF the Seventh European Wave and Tidal Energy Conf., Porto, Portugal.
McCormick M. E. 1981 Ocean Wave Energy Conversion. Wiley Interscience.
McIver P. & Evans D. V. 1988 An approximate theory for the performance of a number of wave-energy devices set into a reflecting wall. Appl. Ocean Res. 10, 5865.
Mei C. C. 1976 Power extraction from water waves. J. Ship Res. 20, 6366.
Mei C. C. 1983 The Applied Dynamics of Ocean Surface Waves. Wiley.
Newman J. N. 1979 Absorption of wave energy by elongated bodies. Appl. Ocean Res. 1, 189196.
Salter S. H. 1974 Wave power. Nature 249, 720724.
Sarmento A. J. N. A. & Falcão A. F. de O. 1985 Wave generation by an oscillating surface-pressure and its application in wave-energy extraction. J. Fluid Mech. 150, 467485.
Smith C. M. 1983 Some problems in linear water waves. PhD thesis, University of Bristol.
Stoker J. J. 1958 Water Waves. Wiley Interscience.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Fluid Mechanics
  • ISSN: 0022-1120
  • EISSN: 1469-7645
  • URL: /core/journals/journal-of-fluid-mechanics
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Full text views

Total number of HTML views: 0
Total number of PDF views: 70 *
Loading metrics...

Abstract views

Total abstract views: 274 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 23rd October 2017. This data will be updated every 24 hours.