A Study of Hydrodynamic Pressures and Wave Loads on Three-Dimensional Floating Bodies

Abstract

The three-dimensional source-sink method or integral equation method, developed by W.D. Kim, C.J. Garrison and others, is now believed to be one of the most versatile methods for the calculation of potential flow field in harmonic oscillation about an arbitrary three-dimensional body. The author extended this method to include procedures for calculating hydrodynamic pressures and wave loads on arbitrary bodies, and conducted calculations on three different types of floating bodies: a circular dock, a rectangular barge of very shallow draft and a one-floater semisubmersible derrick barge. The results of comparison of the calculation with experiments and calculations by other methods revealed that the present method can, by virtue of three-dimensional process, predict very accurately all the characteristics of floating bodies, including motions of six degree of freedom, wave drift force, hydrodynamic pressures and wave loads (shearing & compression forces, bending & torsional moments) in the whole range of frequency of practical interest, and that the conventional methods employing two-dimensional approximation such as the strip method for ships and the Hooft's method for ordinary semisubmersibles cannot give reliable values in the calcualtion of some or all of the characteristics when applied to truly three-dimensional bodies such as treated in this paper.