A linear theory is developed to obtain the motions of a two-dimensional, freely floating body (from which steady intake/discharge flows originate) that encounters incoming waves. The boundary-value problem is formulated within the assumptions of linear potential theory by decomposing the total potential into its oscillatory and steady components. The steady potential is further decomposed into the double-model and perturbation potentials. The time-harmonic potential is coupled with the steady potential through the free-surface condition. The potentials are obtained by use of the quadratic boundary-element method based on the Rankine source. The effect of the steady intake/discharge flows on the diffraction loads, hydrodynamic force coefficients, as well as the motions of a two-dimensional prismatic body floating on the free surface are presented. It is shown that the exciting wave forces and the hydrodynamic coefficients other than the damping coefficients are not appreciably affected in the case of low intake/discharge Froude numbers that are estimated, for example, for a 100 MW floating OTEC plant.

Issue Section:
Technical Papers
Keywords:
marine vehicles, ocean waves, hydrodynamics
Topics:
Damping, Flow (Dynamics), Prisms (Optics), Radiation (Physics), Waves, Boundary-value problems, Boundary element methods, Floating bodies
1.
Ertekin
,
R. C.
,
Qian
,
Z. M.
,
Nihous
,
G. C.
,
Vega
,
L. A.
, and
Yang
,
C.
,
1993
, “
Positioning of a Floating OTEC Plant by Surface Intake Water
,”
Int. J. Offshore Polar Eng.
,
1
, pp.
265
–
272
.
2.
Nihous
,
G. C.
, and
Vega
,
L. A.
,
1993
, “
Design of a 100 MW OTEC Hydrogen Plantship
,”
Mar. Struct.
,
6
(
2–3
), pp.
207
–
221
.
3.
Zhao
,
R.
, and
Faltinsen
,
O. M.
,
1988
, “
Interaction between Waves and Current on a Two-dimensional Body on the Free surface
,”
Appl. Ocean. Res.
,
10
(
2
), pp.
87
–
99
.
4.
Zhao, R., and Faltinsen, O. M., 1990, “Interaction between Current, Waves and Marine Structures,” Proc. 5th Int. Conf. on Numerical Ship Hydrodynamics, Hiroshima, National Academic Press, Washington, D.C., pp. 513–527.
5.
Liu, Y. Z., Ertekin, R. C., and Padmanabhan, B., 1993, “Steady Intake/discharge beneath a Free Surface,” Proc. 2nd Canadian Marine Dynamics Conference, University of British Colombia, Vancouver, B.C., Canada, pp. 57–64.
6.
Ertekin, R. C., Liu, Y. Z., and Padmanabhan, B., 1993, “Interaction of Waves with Intake-Pipe Flow,” Proc. 13th Int. Conf. on Offshore Mechanics and Arctic Engineering, I, ASME, pp. 265–272.
7.
Padmanabhan, B., Ertekin, R. C., and Liu, Y. Z., 1994, “Deformation of Waves in 2-D by a Steady Intake/discharge Flow from a Body,” Proc. Int. Symp. on Waves-Physical and Numerical Modeling, University of British Columbia, Vancouver, B.C., Canada, II, pp. 921–930.
8.
Padmanabhan, B., 1999, “Intake/Discharge Effects on the Hydrodynamics of Floating Bodies,” Ph.D. Dissertation, Department of Ocean Engineering, University of Hawaii at Manoa, Honolulu, Hawaii.
9.
Wu
,
G. X.
,
1991
, “
A Numerical Scheme for Calculating the m-terms in Wave-current-body Interaction Problem
,”
Appl. Ocean. Res.
,
13
(
6
), pp.
317
–
319
.
10.
Ogilvie, T. F., and Tuck, E. O., 1969, “Rational Strip Theory of Ship Motion: Part I,” Department of Naval Architecture and Marine Engineering, College of Engineering, University of Michigin, No. O13.
11.
Nakos, D., 1990, “Ship Wave Patterns and Motions by a Three Dimensional Rankine Panel Method,” Ph.D. Dissertation, Massachussetts Institute of Technology, Cambridge.
12.
Padmanabhan, B., and Ertekin, R. C., 1996, “Interaction of Waves with Floating Structures with Intake/Discharge Flow,” Boundary Element Technology XI, Computational Mechanics Publications, Southampton, UK, pp. 31–40.
13.
Yeung, R. W., 1973, “A Singularity-Distribution Method for Free-Surface Flow Problems with an Oscillating Body,” Rep. No. 73-6 College of Engineering, Univ. of California, Berkeley, CA.
14.
Yeung
,
R. W.
,
1982
, “
Numerical Methods in Free-surface Flows
,”
Annu. Rev. Fluid Mech.
,
14
, pp.
395
–
442
.
15.
Ursell
,
F.
,
1949
, “
On the Heaving Motion of a Circular Cylinder on the Surface of a Fluid
,”
Q. J. Mech. Appl. Math.
,
2
, pp.
218
–
231
.
16.
Nestegard
,
A.
, and
Sclavounos
,
P. D.
,
1984
, “
A Numerical Solution of Two-Dimensional Deep Water Wave Body Problems
,”
J. Ship Res.
,
28
(
1
), pp.
48
–
54
.
17.
Frank, W., 1967, “Oscillation of Cylinders in or below the Free Surface of Deep Fluids,” Rep. No. 2375, Hydromechanics Lab., Naval Ship Research and Development Center, Washington, D.C., October, 39 pp.
Copyright © 2003
 by ASME
You do not currently have access to this content.