Characteristics of Vortex Structure Induced by a Solitary Wave Propagating over a Rectangular Cavity

孤立波通過矩形穴槽時之渦流特性研究

林呈(Chang Lin) ； 何宗浚(Tsung-Chun Ho) ； 張錦鑲(Chin-Shiang Chang) ； 張志華(Chih-Hua Chang)

《海洋工程學刊》 7卷2期 (2007/12) Pp. 1-24

https://doi.org/10.6266/JCOE.2007.0702.01

摘要

本研究係以先進之質點影像測速儀(PIV)以及流場可視化法，對於孤立波通過矩形穴槽時，穴槽周邊流場的渦流脫離運動進行觀察與量測。矩形穴槽模型之展弦比(A(下標 r))介於0.33至無限大，所採用之波高水深比為0.2。本文特別針對展弦比為0.5、1.0 與無限大時，流場中的渦流運動特性進行展示與描述。並在展弦比介於0.33至無限大的實驗條件下，對於流場中的定量特性如主渦渦心運動軌跡、渦心渦度、主渦環流量強度等，進行詳細的分析與討論。

關鍵字

波浪與穴槽交互作用 ； 孤立波 ； 展弦比 ； 渦流 ； 流場可視化

並列摘要

The characteristics of vortex structure induced by a solitary wave propagating over a rectangular cavity are studied experimentally, using particle image velocimetry (PIV) and two flow visualization techniques. The aspect ratio (i.e., ratio of the length to the depth of a cavity, A(subscript r)) of rectangular cavity ranges from 0.33 to infinity in the present study. The ratio of wave height to water depth in the experiment is kept at 0.2. Vortex shedding process is identified particularly for A(subscript r)=0.5, 1.0 and infinity. Detailed vortical structures for A(subscript r)=0.33~∞ were observed using particle trajectory photography or laser induced fluorescence technique. Quantitative characteristics of the primary vortex generated in the cavity, including the trajectories and vorticity of the vortex core and the circulation of the primary vortex, are elucidated in detail.

並列關鍵字

wave-cavity interaction ； solitary waves ； aspect ratio ； vortices ； flow visualization