Vorticity Induced by a Solitary Wave Passing over a Trapezoidal Submerged Breakwater

本研究運用廣義渦旋法（generalized vortex method），進行孤立波通過梯形潛堤之二維流場的數值模擬，研究重點集中於水面波形之變化以及渦流的生成及消散現象。此方法將水面波動產生的非旋性流場以渦層（vortex sheet）表示，而自結構物表面產生之渦流則以帶有渦度之質點離散之。此數值方法可有效減低非線性水波計算的複雜性，並將計算資源集中於具有渦流之處。為驗證模式的正確性，本研究首先進行不同入射波高之非旋性流的模擬，計算所得之波形與他人的研究成果一致。在旋性流的分析當中，探討了渦流的生成對於水面波形及潛堤附近流場的影響。模擬成果發現在波高水深比大於0.1時渦流的生成便具相當程度的影響。隨著波高水深比的增加，所生成之渦流強度亦隨之增加，影響也愈顯著。

關鍵字

孤立波；渦流；潛堤；廣義渦旋法

並列摘要

This research develops a two-dimensional numerical model for the simulation of the flow due to a solitary wave passing over a trapezoidal submerged breakwater on the basis of generalized vortex methods. In this method, the irrotational flow field due to free surface waves is simulated by employing a vortex sheet distribution, and the vorticity field generated from the submerged object is discretized using vortex particles. This method reduces the difficulty in capturing the nonlinear deformation of surface waves, and also concentrates the computational re-sources in the compact region with vorticity. This numerical model was validated by conducting a set of simulations for irrotational solitary waves and then compared with the results of a relevant research. The comparisons exhibit good agreement. The rotational flows induced by different incident wave height were simulated and analyzed to study the effect of vorticity on the deformation of solitary waves and the flow field around the breakwater.

並列關鍵字

solitary wave ； vortex ； breakwater ； generalized vortex method

國際替代計量

Vorticity Induced by a Solitary Wave Passing over a Trapezoidal Submerged Breakwater

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