2008-05-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/697971摘要：波浪通過物體產生的渦流，經常將令流場產生局部性的劇烈變化，現象甚為複雜，對於研究者是一大考驗。從流體力學觀點而言，該現象揉合了表面波的勢流效應及固體邊界層的黏性效應，在數學分析上有相當程度的困難。若使用傳統的黏性流數值方法計算，往往對於尖銳度較高的波浪、或是大小尺度不一的渦旋現象較難處理。 本人與學生提出了結合非旋性與可旋性兩種不同的流體運動概念，並運用邊界積分法與渦旋法建立了同時結合勢流與渦流之數值模式。此嶄新的方法可突破前述困難，對於波浪引致渦流現象的分析提供了一個新方向，並已有初步的具體成果(博士班研究生林孟郁今年一月以此題目獲博士學位)。本研究之目的，在於延續此新穎方法的應用與研發，分列於兩個年度完成。 第一年度為此方法應用在三項不同典型問題之探討：(1)週期波通過矩形潛堤； (2)孤立波通過矩形潛堤；以及(3)波浪通過浮體。工作內容包含問題的計算、成果分析以及論文的撰寫，預計將完成三篇論文投稿至國際期刊。第二年度除了繼續模式的應用，探討斜坡底床產生之渦流對於非線性波浪傳動之效應外，並擬進行方法的研發，工作內容包含運算效率提升，以及與大尺度波潮流水動力模式的銜接。其目的是將此新穎方法實踐於工程問題之應用，以補現有大尺度模式無法完整呈現局部渦流現象的不足。第二年預計將完成兩篇以上論文投稿至國際期刊。 本研究的完成，除了能為黏滯性水波現象的數值方法開創一嶄新的學術道路，透過成果之發表，期望呈現國內在水波數值模擬的研究實力與成果外，並可進一步對於波浪引致渦流的現象提供實際工程之應用。 <br> Abstract: The interaction of surface water waves with submerged structures has attracted attention in many fields of engineering applications. Its mechanism integrates the effects of irrotational flow driven by surface waves and the viscous effects from the separating shear layer on the surface of submerged structures. If the wave profile is steep or the vortex structure is complex, it may be more difficult to study this flow field using a traditional, grid-based numerical scheme. We have proposed a novel method that combines irrotational and rotational characteristics of the flow with free surface and vortices, and established an essentially grid-free scheme using boundary integral method and vortex method (Dr. Meng-Yu Lin was given his PhD degree in January, 2008 for his work on this method). This method may overcome the difficulties mentioned above and provides a new approach to study the interaction of water wave with vortex effect. The aim of this study is to continue the development of this method, including its application and improvement. In the first year of this study, we will investigate the following three typical problems using this method: (a) periodic waves passing over a submerged rectangular dike, (b) solitary waves passing over a submerged rectangular dike, and (c) water waves passing over a floating body. After the analyses of the computational results, we suppose to submit three research papers to international journals. In the second year of this study, one of the tasks is the application of the method to investigate the characteristics of vortex generated in nonlinear waves propagating on a sloping bottom. The other is the improvement of the scheme, including the enhancement of the computational efficiency and the combination with a large-scale hydrodynamic model. The purpose of the improvement is to extend this method to the practical applications in engineering, providing detailed vortex pattern to supplement the insufficient resolution of a large-scale model. We suppose to submit at least two research papers to international journals. In summary, the purpose of this study is to create a different approach to understand the mechanism of vortex generation and evolution in water waves. By the publications of research papers we may demonstrate our capability in investigating water wave problems. We also wish to provide a useful tool for practical engineering applications.波浪結構物渦流wavestructurevortex