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Hydrodynamic effect of heave motion on slow drift oscillation considering finite amplitude motions of a floating body

Conference ·
OSTI ID:55695
 [1];  [2]
  1. Taisei Corp., Tokyo (Japan). Dept. of Civil Engineering Design
  2. Shinozuka Research Inst., Tokyo (Japan)
The authors propose a numerical simulation model to calculate slow drift oscillations taking into account the finite large-amplitude motion of two-dimensional moored floating bodies. The numerical model is based on the Boundary Element Method (BEM) of solving Poisson`s equation in time domain and is dealt with as a moving boundary-value problem. A mixed Lagrangian-Eulerian description is applied to trace particles of a material distributed on the moving free surface. The authors introduce into their model certain innovations, namely: (1) a numerical algorithm for finite large-amplitude motions of a floating body including both the slow drift oscillatory motion due to slowly varying drift forces and the fast varying motion due to first-order wave forces; (2) an adaptive time-stepping treatment of the intersections between the moving free surface and the moving body surface with surge, heave, and roll motions. In this paper they investigate the hydrodynamic effects of heave motion on the slow drift oscillation and the steady drift force. The compare the results conducted by the authors numerical model and Newman`s method for two equal sized moored rectangular floating bodies with two different vertical mooring stiffness. Through the numerical comparisons between their numerical model and Newman`s method, it is clarified that the slowly varying drift forces and the steady drift forces are quite dependent on the heave motion.
OSTI ID:
55695
Report Number(s):
CONF-940230--; ISBN 0-7918-1264-2
Country of Publication:
United States
Language:
English