On the estimation method of hydrodynamic forces acting on a very large floating structure. Part 2

An estimation method of the hydrodynamic radiation forces on a very large b ox-shaped floating structure is proposed. This is an extension of a previou s paper (Kagemoto H, Fujino M, Zhu T. On the estimation method of hydrodyna mic forces acting on a very large floating structure. Applied Ocean Researc h 1997;19:49-60), in which a diffraction problem was dealt with. In the pre sent paper, radiation problems resulting from forced motions of a very larg e floating structure including elastic mode of motions are analyzed. By exp loiting the fact that, when the horizontal dimension of the corresponding s tructure is very large, the velocity potential over the bottom surface of t he structure has the same spatial distribution as that of the local displac ement of the structure, it is shown that the computational burden can be re duced drastically without losing accuracy. As a byproduct of these computat ions, an interesting feature is found that damping forces acting on the bot tom surface of the corresponding structure are very small except near the p erimeters of the structure. In order to demonstrate the efficaciousness of the presented methods, the f ollowing are analyzed: (a) elastic responses of a very large box-shaped str ucture in waves; and (b) wave forces on floating airports composed of two r unway structures. (C) 1999 Published by Elsevier Science Ltd. All rights re served.