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Wave generation by an oscillating surface-pressure and its application in wave-energy extraction

Published online by Cambridge University Press:  20 April 2006

A. J. N. A. Sarmento  and
A. F. de O. Falcão
A. J. N. A. Sarmento
Affiliation:
Mechanical Engineering Department, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1096 Lisboa Codex, Portugal
A. F. de O. Falcão
Affiliation:
Mechanical Engineering Department, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1096 Lisboa Codex, Portugal
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Abstract

A two-dimensional analysis, based on linear surface-wave theory, is developed for an oscillating-water-column wave-energy device in water of arbitrary constant depth. The immersed part of the structure is assumed of shallow draught except for a submerged vertical reflecting wall. Both the cases of linear and nonlinear power take-off are considered. The results show that air compressibility can be important in practice, and its effects may in general be satisfactorily represented by linearization. The analysis indicates that using a turbine whose characteristic exhibits a phase difference between pressure and flow rate may be a method of strongly reducing the chamber length and turbine size with little change in the capability of energy extraction from regular waves. It was found in two examples of devices with strongly nonlinear power take-off that the maximum efficiency is only marginally inferior to what can be achieved in the linear case.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 150 , January 1985 , pp. 467 - 485
Copyright
© 1985 Cambridge University Press

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