臺灣博碩士論文加值系統

本文實驗係利用大氣環境風洞模擬都市地形之中性大氣紊流邊界層流，並量測在具不同斜坡角度之三角形地形之下風坡角處氣懸性污染排放於建築物與街谷之濃度擴散特性。由實驗量測結果分析探討，獲致以下結論：
一、本文利用環境風洞搭配合適之渦流產生器與粗糙元素之組合，模擬出本實驗所需之都市地形中性大氣紊流邊界層，其風場各項特性(包括平均風速剖面、紊流強度剖面)均符合Counihan(1975)[1]實場結果之建議值範圍內。
二、污染氣團煙流在流經建築物時，會因建築物的影響呈現濃度抬升，但抬升現象隨著下游距離增加而趨緩。
三、污染氣團之垂直向擴散尺度分析結果顯示，除了受建築物影響導致擴散尺度有變化外，另沿下游擴散尺度增加而趨緩。而水平向擴散尺度除排放源鄰近出口區段有些微變化外，其沿下游變化很小且趨緩。
四、受建築物阻擋影響導致污染氣團質心位置高度有明顯上升外，街谷後方建築物下游區質心位置高度之變化並不大且趨近平緩。

In the present thesis, wind tunnel experiments were conducted to study the dispersion characteristics of the airborne pollution on the triangle terrain with different slope angles and various distances between the terrain and street canyons.
In the experiments, the airborne pollution source was located at the toe of the downwind slope of terrain. The triangle terrain with equal upwind and downwind slope which were 15∘and 30∘. Building heights in the street were the same with terrain model height. The height denoted by H. The vortex generators and roughness elements were appropriately arranged in the test section of wind tunnel to simulate the neutral atmospheric boundary layer flows which used as the approaching flow for the experiments. The distance between the triangle terrain and front row building of street canyon were 2H and 4H. Effects of the downwind slope angle of terrain and the distance between the triangle terrain and front row building of street canyon on the pollution dispersion characteristics (such as pollution plume averaged height and dispersion parameters) were investigated in this study.

摘要 I
ABSTRACT II
目次 III
表次 V
圖次 VI
符號說明 IX
第一章 導論 1
1-1 前言 1
1-2 研究目的 1
1-3 文獻回顧 2
1-4 研究方法 2
第二章 風洞實驗模擬之理論分析 5
2-1 大氣紊流邊界層 5
2-2 中性大氣紊流邊界層之風洞試驗模擬 5
2-2-1 渦流產生器設計原理 6
2-2-2 粗糙元素設計原理 7
2-3 中性大氣紊流邊界層之風場特性 8
2-3-1 平均風速剖面 8
2-3-2 紊流強度剖面 9
2-3-3 紊流積分尺度 11
2-3-4 紊流能譜 11
2-4 風洞模擬大氣污染濃度擴散 12
2-4-1 高斯擴散理論 12
2-4-2 煙流擴散尺度 13
2-4-3 結構物對於煙流擴散之影響 14
2-5 相似性法則 15
2-6 濃度因次分析 17
第三章 實驗設計與配置 21
3-1 實驗程序 21
3-2 實驗儀器系統 21
3-2-1 大氣環境風洞 22
3-2-2 風場量測系統之儀器 23
3-2-3 濃度場量測系統之儀器 24
3-3 實驗設計 25
3-3-1 模型設計與排列配置 25
3-3-2 迫近流場模擬設計 26
3-3-3 迫近流場量測設計 27
3-3-4 濃度擴散煙流模擬設計 27
3-3-5 濃度分析之模擬設計 28
3-3-6 濃度場採樣點設計 28
第四章 實驗結果分析與討論 31
4-1 迫近流場之模擬結果 31
4-1-1 平均風速剖面 31
4-1-2 紊流強度剖面 32
4-1-3 紊流能譜 33
4-2 濃度場擴散特性之分析討論 34
4-2-1 斜坡15∘三角形地形與街谷間距2H之濃度擴散分析 34
4-2-2 斜坡30∘三角形地形與街谷間距2H之濃度擴散分析 34
4-2-3 斜坡15∘三角形地形與街谷間距4H之濃度擴散分析 35
4-2-4 斜坡30∘三角形地形與街谷間距2H之濃度擴散分析 36
4-3 擴散尺度之分析討論 36
4-4 質心位置之分析討論 37
4-5 垂直向之地表濃度及最大濃度之比較分析討論 37
4-6 建築物表面濃度之分析討論 38
4-7 不同斜坡角度地形與相同街谷間距之擴散特性分析討論 38
4-8 不同斜坡角度地形與街谷中心處之濃度剖面比較 39
第五章 結論 41
參考文獻 42
附表 44
附圖 46
誌謝 98

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