Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/13563
標題: 紊流邊界層中點污染源擴散之視化研究
Visualization of Point-Source Dispersion in Turbulent Bounbary Layers
作者: 許志祥
Hsu, Chih-Hsiang
關鍵字: Water Tunnel Testing;水洞試驗;Point-Source Dispersion;擴散尺度;大氣邊界層
出版社: 土木工程學系
摘要: 
本研究旨在應用水洞試驗,並配合影像視化技巧及圖像數位化處理之
方法,研究惰性 及非沉降性之污染物在中性穩定大氣邊界層內的擴散行
為。 研究結果發現無論在水平方向或
垂直方向上,染料擴散之長時間平均擴散尺度均會隨 點源下風距離之增
加而增加。而且水平方向之時均擴散尺度大致上隨距離地表高程的昇高
而遞減,最後保持穩定不變,僅於靠近地表附近會有微增或保持不變的趨
勢。於垂直方向 之時平均擴散尺度則因有地表邊界的限制,在地表附近
擴散較小然後隨距離地表高程之增 加而增加,直至擴散達到某一最高值
後則隨高程之增加而遞減,最後呈微量遞減或不變。 研究中亦以數
學式迴歸水平向與垂直向之時均擴散尺度,結果發現水平向的迴歸結果
比較好;而垂直向的迴歸結果則並不理想,主要是因為有地表邊界限制之
影響。

Mechanisms of point-source dispersion are investigated in a
water tunnel with three types of approaching flows, cor-
responding respectively to rural, suburb and urban ground
conditions. The non suspended pollution is produced by in-
jecting fluorescent solution to the flow. By using a image
processing technique, the instantaneous concentration fields,
in forms of laser-sheet profiles, are pictured and then con-
verted into digital forms. These are con- ducted for a suffi-
ciently long period for further statistical analyses.
In the study, the variations of the dispersion scales
(horizontal and ver-tical) with respect to the downstream
distance, the release height and the ground condition are
measured and analyzed. Additional regressed relationshipsare
also proposed for future related applications.
URI: http://hdl.handle.net/11455/13563
Appears in Collections:土木工程學系所

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