Nonbreaking Wave Forces on Multiresonant Oscillating Water Column Wave Power Caisson Breakwater
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 131, Issue 2
Abstract
Experimental measurements of in-line wave forces on a 1:50 scale model of an array of multiresonant oscillating water columns (MOWCs), a free-standing wave energy caisson, are reported. Wave forces on a vertical wall were measured and compared with Sainflou’s and Goda’s formulas, which serve as base for studying wave forces on an MOWC array. A range of hydrodynamic parameters with different damping of the OWC chamber and center-to-center (c/c) spacing were used. In general, the force on the MOWC caisson array is twice that of the vertical wall for maximum damping of the OWC chamber. Reduction of damping of the OWC air chamber reduces the force on the array of caissons by 35–60% of the force on a vertical wall. It is found that shoreward force magnitude is greater than seaward. For spacing of 2–3 times the harbor width, the OWC array acts like a perforated breakwater, experiencing 60% of wave forces on the vertical wall, while for a c/c spacing range of 4–5, it behaves like a vertical wall. Incorporation of an air pressure release by pass system for the OWC chamber is recommended, as this will reduce in-line wave forces on a caisson array to a range of about 35–40%. The nonlinear response of the OWC on wave forces warrants the use of a numerical model and further investigation.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The writers wish to acknowledge the support of the Department of Ocean Development, Government of India, for funding the research and development activities on wave energy. The writers are grateful to the Wave Energy Group of the Indian Institute of Technology Madras, Chennai, India, for their help and encouragement and all the project staff for their assistance during the investigations.
References
Ambli, N., Bonke, K., Malmo, O., and Reitan, H. (1982). “The Kvaerner multiresonant OWC.” Proc., 2nd Int. Symp. on Wave Energy Utilization, Tapir, Trondheim, Norway, 275–295.
Brendmo, A., Falnes, J., and Lillebekken, P. M. (1996). “Linear modelling of oscillating water columns including viscous loss.” Appl. Ocean. Res., 18, 65–75.
Carmichael, A. D. , and Falnes, J. (1992). “State of the art in wave power recovery.” Proc., Int. Conf. on Ocean Energy Recovery: the State of the Art, ASCE, New York, 182–212.
Clement, A. H. (1997). “Dynamic nonlinear response of OWC wave energy devices.” Int. J. Offshore Polar Eng., 7(2), 154–159.
Coastal Engineering Research Center (CERC). (1984). Shore protection manual, 4th Ed., U.S. Army Waterways Experiment Station, Washington, D.C.
Count, B. M., Fry, R., and Haskell, J. (1983). “An experimental investigation of the harbor concept in wave energy.” Research Rep. TPRD/M/1208/N83, Central Electricity Generating Board, Marchwood Engineering Laboratory, Southampton, U.K.
Goda, Y. (1974). “New wave pressure formula for composite breakwaters.” Proc., 4th Int. Conf. on Coastal Engineering, ASCE, New York, 1702–1720.
Goda, Y. (1985). Random seas and design of maritime structures, University of Tokyo, Tokyo.
Holman, J. P. , and Gajda, W. J. , Jr. (1989). Experimental methods for engineers, McGraw-Hill, New York.
Jayakumar. (1994). “Wave forces on oscillating water column type wave energy caisson: an experimental study.” PhD thesis, Dept. of Ocean Engineering, Indian Institute of Technology, Madras, India.
Kaldenhoff, H. (1990). “Breakwaters—layout and design.” Rep. of Short Term Course, Ocean Engineering Centre, Indian Institute of Technology, Madras, India.
Koola, P. M. (1990). “Investigations on the performance behavior of oscillating water column wave energy device.” PhD thesis, Ocean Engineering Centre, Indian Institute of Technology, Madras, India.
Muller, G. U. , and Whittaker, T. J. T. (1993). “An investigation of breaking wave pressures on inclined walls.” Ocean Eng., 20(4), 349–358.
Muller, G. U. , and Whittaker, T. J. T. (1995). “Visualization of flow conditions inside a shoreline wave power station.” Ocean Eng., 22(6), 629–641.
Sainflou, G. (1928). “Essai sur les diques maritimes verticals.” Ann. Ponts Chaussees, 98(1), 5–48 (in French).
Sarmento, A. J. N. A. , and Brito-Melo, A. (1995). “An experiment-based time-domain mathematical model of OWC power plants.” Proc., 5th Int. Offshore and Polar Engineering Conf., International Society of Offshore and Polar Engineers, Cupertino, Calif., 321–327.
Sarmento, A. J. N. A. and Falcao, A. F. O. (1985). “Wave generation by an oscillating surface pressure and its application in wave energy extraction.” J. Fluid Mech., 150, 467–485.
Shaw, R. (1982). Wave energy: a design challenge, Ellis Horwood, Chichester, U.K.
Takahashi, S. (1988). “A study on design of a wave power extracting caisson breakwater.” Rep. from Wave Power Laboratory, Port and Harbor Research Institute, Tokyo.
Thiruvenkatasamy, K. (1994). “An experimental investigation on wave forces, air pressures, and optimum spacing of oscillating water column wave energy caissons in array.” MS thesis, Ocean Engineering Centre, Indian Institute of Technology, Madras, India.
Denniss, T. (2002). “Parabolic shaped reflector to concentrate wave resource on the OWC.” ⟨http://www.energetech.com.au/content/company.html⟩ (July 30, 2003).
Whittaker, T. J. T. , and Stewart, T. P. (1993). “An experimental study of nearshore and shoreline oscillating water columns with harbors.” Proc., European Wave Energy Symposium, Natural Engineering Laboratory, East Kilbride, U.K., 151–156.
Information & Authors
Information
Published In
Copyright
© 2005 ASCE.
History
Received: Dec 4, 2001
Accepted: Sep 24, 2004
Published online: Mar 1, 2005
Published in print: Mar 2005
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.