Abstract

In this paper, a three-dimensional numerical wave tank was implemented based on Fluent software, and loads of focusing waves passing through a four-column vertical array at different focusing position and incident angle wre studied. The results showed that when the focusing position of the same wave was at the front column, the center position and the back column, the focusing wave load peaks are different, and the peaks of the wave load varied with the focusing wave period and wave incident angle. Under the action of wave focusing from different incidence angles, the relative position of the cylinder changed, resulting in different positions of peak frequency in high-frequency wave loads. Consequently, to determine the maximum possible focusing wave loads on the column group structures, multiple calculations at different focusing positions are necessary.

INTRODUCTION

With the development of marine resources gradually moving from nearshore to open sea, various deep-sea floating structures are subjected to more severe marine environment. How to ensure the safety of structures has become a hot topic in the field of ocean engineering in recent years. Focusing waves have been paid more attention by researchers, which can cause great damage to the structure (Walker, 2004).

Longuet-Higgins (1952) studied the statistical characteristics of extreme waves for the first time. Baldock (1996) generated extreme waves through the superposition of multiple linear regular waves. Turnbull (2003) simulated the generation of focusing waves through the finite element method of s transformation, and Johannessen (2001) studied the focusing wave train through double Fourier transform. Tromans (1991) proposed a New-Wave Theory that could simulate extreme waves with specific wave amplitude. Westphalen (2008) used commercial software Star CCM+ and CFX, Bihs (2016) used Reef3D and Hu (2016) used open source software OpenFoam to generate the focusing waves by giving the velocity entry boundary conditions.

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