波浪與浮式結構物互相作用之理論解析

Analytic Solution of Waves Acting on Floating Structures

陳伯義(Po-I Chen) ； 李兆芳(Jaw-Fang Lee) ； 洪偉勝(Wei-Sheng Hong)

《海洋工程學刊》 6卷2期 (2006/12) Pp. 63-80

https://doi.org/10.6266/JCOE.2006.0602.04

摘要

本文對於浪作用於浮式結構物互相作用的問題提出理論解析解。文中考慮垂直二維問題，浮式結構物為矩形，具有水平(surge)、垂直(heave)、轉動(pitch)等三個運動自由度。在問題求解方法上為將入射波引發結構物運動的互相作用問題，分解為散射問題與三個方向的單位振幅結構物運動之輻射問題，最後利用結構物運動方程式合併求解整個問題。理論求解散射問題以及結構物水平方向運動和垂直方向運動之輻射問題，在文獻中已有完整敘述，本文主要貢獻為先提出單位振幅結構物轉動之輻射問題的理論解析解，然後合併散射問題與三個自由度的輻射問題來描述結構物運動。上述散射問題與輻射問題的解析結果，配合結構物運動方程式，可求解得到浮式結構物與波浪互相作用的理論解析解。利用本文的解析解計算浮式結構物之運動，與波浪的反射係數，與Ijima(1972)的數值計算結果比較，顯示很好的一致性。

關鍵字

浮式結構物 ； 理論解析 ； 三個自由度 ； 輻射問題

並列摘要

The purpose of this study is to present a theoretical solution for the linearlized problem of incident waves acting on a floating structure. The problem considered is two-dimensional vertically, the floating structure is rectangular, and the motion is of three degrees of freedom. The problem is separated into a scattering problem and radiation problems with unit motion amplitudes, in three directions, and the problem is finally solved by using equations of motion of the floating structure. Analytic solutions for the scattering problem, radiation problems of surge motion and heave motion have already shown in the literature. Main contributions of this study are that the radiation problem of the pitch motion with unit amplitude is proposed first, and motions of the floating structure with three degrees of freedom are solved theoretically. By combining the scattering solution, radiation solutions of three degrees of freedom, and equations of motion of the floating structure, an analytic solution for the problem is developed. The presentt analytical solution is compared with Ijima (1972) using a numerical method and the comparsion show very good agreement. Using the preaent theory characteristics of the structural motions as well as reflectiong and transmitting waves can be caculated.

並列關鍵字

floating structure ； analytical solution ； three degrees of freedom ； radiation problem