ABSTRACT:

A numerical method for calculating the steep wave forces on a group of large vertical cylinders located In any water depth is described In this paper. The Procedure is based on Rienecker and Fenton"s (1981) Fourier approximation wave theory. The calculated results for wave forces on single surface piercing cylinder and different group of vertical cylinders are compared with the available experimental and site measured data. The agreements are quite favourable.

INTRODUCTION

As offshore construction continues to expand the world a wide range of design and construction problems are being encountered. Basic to many such problems Is wave forces on a group of large vertical cylinders located In arbitrary water depth since the application of large vertical cylinders In offshore structures is manifold and many such structures Include multiple cylindrical legs. Therefore, there Is an Increasing need to Improve the understanding of effects of water waves on different group of cylinders, develop a practical prediction method for application in such structure design. Wave load and response calculations for slender structures generally employ the Morison equation, which Is based on the assumption that the Incident wave kinematics do not change significantly In the vicinity of the structures. On the other hand, the general treatment of wave Interactions with large structures, which extend horizontally more than about a fifth of wave length is quite different from that of slend structure. The computation of wave force on a single large virtical cylinder has traditionally been based on linear diffraction theory (e.g. MacCamy and fuchs (1954): Hogben (1974): Sllrphya and Isaacson (1981): Isaacson and Wu (1983). etc). Although linear diffraction theory gives extremely good results for most design situations, there are many Instances where non-linearities become Important and wave forces become notably large- -particularly for steep shallow wave conditions.

This content is only available via PDF.
You can access this article if you purchase or spend a download.