年度 99
計劃編號 NSC99-2221-E-002-222-
研究學門 近海及離岸工程
中文計劃名稱 潛沒式平板造成之波浪散射與渦流生成
執行期限 2010-08-01～2011-07-31
主持人 黃良雄
職稱
預算 611000
中文摘要 為避免人工構造物破壞自然景觀，潛沒式消波結構物愈來愈受到重視。潛沒式平板對於環境的衝
擊較小，符合現今生態環保意識，然而其流體水動力特性亦較複雜，因此在學理分析上增加了許多困
難。
關於水波通過潛沒式平板的研究多應用勢流理論（potential flow theory），然而實驗研究卻顯示量
測數據與勢流理論分析有相當出入，其主因為勢流理論忽略了平板端點的渦流效應，而此渦流會造成
流速劇烈變化並對平板受力具支配性的影響，故其效應不可忽略。
為突破勢流理論的缺點，以及擺脫一般黏性水波計算受網格之限制，本研究乃擬結合非旋性與可
旋性兩種不同的流體運動概念，並應用邊界積分法與渦漩法 (vortex method)，進行水波與潛沒式平板
相互作用之研究。此方法主體在本人過去主持之計畫[NSC 92-2611-E-002-030, NSC 93-2611-E-002-012]
已完成。此方法固可免除網格建立的時間耗費以及處理自由水面邊界的困難，並將計算資源集中於具
旋性的區域內，因此在處理水波與渦旋現象上具有優勢，但由於平板極薄以致邊界上的速度不易計
算，非原始計算程式所能處理，故仍需進一步克服。
本研究擬分析水波通過潛沒式薄平板之波浪變形及渦流生成等水流現象，以獲得更接近實驗數據
的結果，並分析平板的受力情形，特別是渦流對於平板產生的阻、昇力以及轉矩，以作為平板結構物
穩定分析之參考，並供實際工程之應用。
英文摘要 Submerged breakwaters have attracted attention in recent years because ecological and environmental issues
have become increasingly important. A submerged flat plate has reduced environmental and visual impacts,
but the interaction of water waves with a submerged plate is more complex than that with a blunt body.
Many studies of free surface flow with a submerged plate have been performed using potential-flow
theory. However, experimental investigations of this topic reveal significant discrepancies between the
measurement data and the theoretical results using potential-flow theory. This can be attributed that these
analyses using potential-flow theory ignore the effects of vortices generated from the edges of a plate. These
vortices lead to considerable fluctuations of flow velocity and have dominant influence on the hydrodynamic
force on a plate; therefore, the effects of vortices should not be ignored.
To overcome the drawback of a potential-flow analysis of this topic as well as the limitation of a
computation caused by grid resolution, this study develops a novel numerical method to investigate the
interaction of water waves with a submerged flat plate by integrating the different concepts between
irrotational and rotational motion of fluid and by employing boundary integral methods and vortex methods.
The main framework of this method was established in my previous projects [NSC 92-2611-E-002-030, NSC
93-2611-E-002-012]. Although this method is capable of capturing the moving free surface and vortices
more efficiently and reasonably and can concentrate computational resources in rotational regions, the special
geometry of a plate still leads to numerical difficulties. For a thin plate, evaluating the slip velocity (or
strength of vortex sheet) on its boundary is difficult; therefore, further study in numerical implementations of
this problem is required.
This study will investigate wave scattering and vortex generation due to the interaction of water waves
with a submerged flat plate, and more reasonable results (compared with experimental measurements) will be
expected. This study will also analyze the drag, lift and torque of the submerged plate. The results of this
research may provide useful information for the instability analysis and for engineering applications of a
submerged plate as a wave scattering structure.
中文關鍵字 潛沒平板,水波,邊界積分法,渦漩法
英文關鍵字 submerged horizontal plate,water waves,boundary integral method,vortex method
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