岸邊多重突起所引致之斜面波研究

Abstract

沿岸水域的研究者常指出，沿岸斜面地形變化往往影響沿岸水域波高 變化。然而沿岸斜面地形變化與沿岸水域波高關係之解析解仍有發展空間，因此本研究旨在探討不同沿岸斜面地形與該水域波高之間關係。如以無旋流與密度為定值考慮之，可獲得不同沿岸斜面形狀之流場解析解。本論文架構由以下二部份所組成。第一部份為使用微擾展開法(Perturbation Method)配合傅利葉積分(Involving Fourier-Integral Theorem)及商末菲德輻射條件(Sommerfeld Radiation Condition)，獲得不同沿岸斜面地形所引起沿岸波形斜面之水面波動解析解。第二部份，則探討半圓柱形突起或是凹陷的斜面地形組合後，對水位影響以及流域之影響。總結而言，此研究希望能解釋沿岸斜面地形變化與水波高度之間關係，也可提供海洋相關研究人員在探討沿岸流場上更為了解變動沿岸斜面與沿岸海域波高之互制現象。

Researchers of edge waves have often suggested that the varying longshore topography of sloping beach would affect wave heights in flowfields. However, research which has analytical solutions the link betweenalongshoretopographies and waveheightsisscant.Therefore,theaimofthis article attempts to explore how varying longshore topographies of sloping beaches and wave heights are related. For solving this problem in analytic way, we mark some assumptions for simplification: Assuming this is incompressible and irrotational flow in three-dimensional flow field. The framework of this study is divided into two parts. The first part is to set up the governing equations for several difference beds. The analytical solutions are obtained by the perturbation method, the method involving Fourier-Integral theorem, and the Sommerfeld s part radiation condition. The second part is considering the interaction between wave and flow in difference beds. To conclude, this study may be of importance in explaining the relationship between varying longshore topographies and wave heights, as well as in providing ocean engineers with a better understanding of edge waveson coastalocean.