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Slow-drift motion of a two-dimensional block in beam seas

Published online by Cambridge University Press:  20 April 2006

Yehuda Agnon  and
Chiang C. Mei
Yehuda Agnon
Affiliation:
Woods Hole Oceanographic Institution and Massachusetts Institute of Technology
Chiang C. Mei
Affiliation:
Massachusetts Institute of Technology
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Abstract

Because of the inherent nonlinearity in the boundary conditions on the free surface, water waves with frequencies from neighbouring parts of the sea spectrum interact and force low-frequency oscillations at the second order. Since the physical phenomenon involves vastly different timescales, the perturbation method of multiple scales is applied here to a rectangular cylinder in beam seas. It will be shown that at the second order there are two kinds of long waves; one is locked to the envelopes of the incident, reflected and transmitted short waves, while the other propagates away from the body at the long-wave velocity (gh)½. The latter contributes to the damping of slow-drift oscillations of the body. Analytical results for the displacement amplitudes of the slow sway and for the radiated long waves are derived. The transient evolution due to incident envelopes of finite and semi-infinite duration is also predicted.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 151 , February 1985 , pp. 279 - 294
Copyright
© 1985 Cambridge University Press

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References

Faltinsen, O. M. & Loken A. E.1979 Slow drift oscillations of a ship in irregular waves. Appl. Ocean Res. 1, 21–31.Google Scholar
Hsu, F. H. & Blenkarn K. A.1970 Analysis of peak mooring forces caused by slow vessel drift oscillations in random seas. Proc. Offshore Technol. Conf., Houston; Paper 1159.Google Scholar
Longuet-Higgins M. S.1977 The mean forces exerted by waves on floating or submerged bodies, with applications to sand bars and wave-power machines Proc. R. Soc. Lond. A 352, 463–480.Google Scholar
Longuet-Higgins, M. S. & Stewart R. H.1964 Radiation stress in water waves; a physical discussion with application. Deep-Sea Res. 11, 529–562.Google Scholar
Mei C. C.1983 The Applied Dynamics of Ocean Surface Waves. Wiley-Interscience.
Molin, B. & Bureau G.1980 A simulation model for the dynamic behavior of tankers moored to single point moorings. Proc. Intl Symp. on Ocean Engineering Ship Handling, Swedish Maritime Research Center, Gothenburg.
Newman J. N.1974 Second order, slowly varying forces on vessels in irregular waves. Proc. Intl Symp. on Dynamics of Marine Vehicles and Offshore Structures in Waves, University College London.
Ogilvie T. F.1983 Second-order hydrodynamic effects on ocean platforms. Paper presented at Intl Workshop on Ship and Platform Motions, University of California at Berkeley.Google Scholar
Pinkster J. A.1976 Low frequency second order wave forces on vessels moored at sea. Proc. 11th Symp. on Naval Hydrodynamics, University College London.
Pinkster J. A.1980 Low frequency second order wave exciting forces on floating structures. Netherlands Ship Model Basin Publ. 650.
Remery, G. F. M. & Hermans A. J.1971 The slow drift oscillations of a moored object in random seas. Proc. Offshore Technol. Conf., Houston.
Triantafyllou M. S.1982 A consistent hydrodynamic theory for moored and positioned vessels. J. Ship Res. 26, 97–105.Google Scholar