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Journal of Applied Mathematics
Volume 2012 (2012), Article ID 142850, 27 pages
Research Article

Hydrodynamics of a Free Floating Vertical Axisymmetric Oscillating Water Column Device

Laboratory for Floating Structures, Mooring Systems and Division of Marine Structures, School of Naval Architecture and Marine Engineering, National Technical University of Athens, 9 Heroon Polytechniou Avenue, GR 157-73 Athens, Greece

Received 22 January 2012; Accepted 12 September 2012

Academic Editor: Carl M. Larsen

Copyright © 2012 S. A. Mavrakos and D. N. Konispoliatis. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper aims at presenting a general formulation of the hydrodynamic problem of a floating or restrained oscillating water column device. Three types of first-order boundary value problems are investigated in order to calculate the velocity potential of the flow field around the device. The horizontal and vertical exciting wave forces, the rolling moment, the hydrodynamic parameters, the volume flows, and the drift forces are obtained in order to find the loads on the structure. The efficiency rate of the device is calculated in connection with the absorbed power and the capture length of energy absorption. Finally, the resulting wave motion inside and outside the device and the inner air pressure are examined.