臺灣博碩士論文加值系統

環境風場議題為風工程領域中不可忽視的議題之一，在許多國家皆有造成行人不舒適甚至傷亡的案例，一個被判定為不舒適的環境風場會影響到建築物周邊環境的使用用途與區域規劃，有關環境風場的評估與改善措施，已成為設計時必須考量的項目之一。

本研究欲利用計算流體力學(CFD；Computational Fluid Dynamics)模擬，搭配過去的學者研究成果，於風工程領域中進行環境風場議題的研究，以建立合適之數值模擬模式。而本研究內容分為三個部份，第一部份為使用CFD模擬懸崖、山脊及山丘三種特殊地形之加速效應，藉由比較CFD模擬結果與兩種耐風規範(『建築物耐風設計規範與解說』(2015)、National Building Code of Canada(2005))所提供之規範值，來確立CFD模式選擇與參數設定之正確性。在比較結果中發現CFD模擬結果較為接近NBCC(2005)提供之規範值；和NBCC(2005)相比，近地面區域之模擬誤差(8~10%)明顯大於所有區域之平均誤差(3~5%)。第二部份與第三部分分別為以CFD模擬風經過一棟1:1:2之獨立建築物和以CFD模擬風經過都市區域後所產生之風加速效應，並與日本建築學會AIJ(Architectural Institute of Japan)於網站上所提供之風洞試驗結果做比較，以找尋較為妥當的建築物周邊風場之CFD模擬模式。在比較結果中發現兩部分之CFD模擬結果與風洞試驗風速分布之趨勢大致相同，在行人高度處，角隅風流影響區域(高風速區域)之模擬較為良好(誤差約10%)，在建築物背風側(低風速區域)之模擬則較為失準(誤差約32%)。

此外，在第二部分與第三部分皆會進行環境風場評估流程，在評估結果中發現，在高雄之盛行風向下，第二部分與第三部分之模擬結果皆會引起行人不舒適之情況；為降低加速比而選擇以防風植栽及遮風棚架進行模擬，發現防風植栽及遮風棚架可以使建築物周邊之風場合乎行人舒適度評估標準，植栽能使風速較大之測點下降約14.5%之風速，而棚架能使風速較大之測點下降約19.7%之風速。

Pedestrian wind environment is a very important issue which can not be ignored since an uncomfortable wind environment would affect the usability and planning of the region around the building. The pedestrian wind comfort assessment and improvement become an important issue when building a highrise building.

This study simulates wind speed-up effect of the pedestrian wind environment by Computational Fluid Dynamic (CFD). The first part of this study is the comparison between the simulation results of the wind speed-up effect around escarpment, ridge and hill by CFD and those specified in Taiwan Code(2015) and National Building Code of Canada(2005). It shows that the CFD simulation results are closer to those provided in NBCC (2005), and the simulation error (8~10%) in the near-ground region is larger than the average error (3~5%). The second part and the third part of this study are respectively the simulation of the wind speed-up effect around a 1:1:2 independent building and that in an urban area. By comparing with the wind tunnel test results provided by Architectural Institute of Japan (AIJ), the CFD simulation results in the region affected by the corner flow (high wind region) at the pedestrian height are relatively good (about 10% error), and those on the leeward side of the building (low wind region) are relatively inaccurate (about 32% error).

In addition, it is found that based on the simulation results, pedestrian discomfort will occur under Kaohsiung prevailing wind. The windbreak vegetation can reduce 14.5% of the highest wind speed while the windbreak canopy can reduce 19.7% of the highest wind speed.

第一章 緒論1
1.1 研究緣起1
1.2 論文架構3

第二章 文獻回顧5
2.1 前言5
2.2 大氣邊界層5
2.2.1 平均風速剖面5
2.2.2.1 對數率剖面6
2.2.2.2 指數律剖面7
2.2.2.3 台灣耐風規範規定之平均風速剖面8
2.2.2 紊流剖面9
2.3 地形對平均風速剖面之影響10
2.4 環境風場11
2.4.1 有關環境風場之風場特性11
2.4.2 環境風場評估指標13
2.4.3 環境風場評估流程14
2.4.4 環境風場改善措施15

第三章 數值模擬方法28
3.1 CFD的介紹28
3.1.1 CFD模擬的優缺點28
3.1.2 CFD模擬的執行流程29
3.1.3 CFD於風工程相關準則之發展30
3.2 控制方程式之決定31
3.2.1 大氣尺度31
3.2.2 控制方程式推導33
3.3 紊流模型36
3.3.1 標準 k-ε 模型36
3.3.2 RNG k-ε 模型37
3.3.3 Realizable k-ε 模型38
3.4 壁面處理39
3.4.1 對Law of the wall之模擬41
3.4.2 對壁面粗糙度之模擬42
3.5 離散化43
3.6 求解方法45

第四章 特殊地形加速效應之CFD模擬56
4.1 前言56
4.2 懸崖57
4.2.1 幾何外型設定57
4.2.2 計算區域設定58
4.2.3 邊界條件設定58
4.2.4 其他設定60
4.2.5 設定參數之檢核60
4.2.5.1 收斂性之驗證61
4.2.5.2 網格獨立性之驗證61
4.2.5.3 計算域大小之檢核62
4.2.6 模擬結果分析與比較63
4.3 山脊65
4.3.1 幾何外型設定65
4.3.2 計算區域設定66
4.3.3 邊界條件設定66
4.3.4 其他設定66
4.3.5 設定參數之檢核66
4.3.6 模擬結果分析與比較66
4.4 山丘69
4.4.1 幾何外型設定69
4.4.2 計算區域設定69
4.4.3 邊界條件設定69
4.4.4 其他設定70
4.4.5 設定參數之檢核70
4.4.6 模擬結果分析與比較70
4.5 小結71
第五章 獨立建築物周邊風場效應之CFD模擬89
5.1 前言89
5.2 幾何外型設定90
5.3 計算區域設定90
5.4 邊界條件設定90
5.5 其他設定92
5.6 設定參數之檢核92
5.6.1 收斂性之驗證93
5.6.2 網格獨立性之驗證93
5.6.3 計算域大小之檢核94
5.7 模擬結果分析與比較95
5.8 環境風場舒適度評估99
5.9 改善方式之探究101
5.9.1 改善方式之選擇101
5.9.2 改善方式之設定102
5.9.3 改善結果之觀察103
5.9.4 改善結果之舒適性評估104
5.10 小結105

第六章 都市高樓周邊風場效應之CFD模擬128
6.1 前言128
6.2 幾何外型設定129
6.3 計算區域設定129
6.4 邊界條件設定130
6.5 其他設定131
6.6 設定參數之檢核132
6.6.1 收斂性之驗證132
6.6.2 網格獨立性之驗證132
6.6.3 計算域大小之檢核133
6.7 模擬結果分析與比較134
6.8 環境風場舒適度評估136
6.9 改善方式之探究137
6.9.1 改善方式之選擇137
6.9.2 改善方式之設定137
6.9.3 改善結果之觀察138
6.9.4 改善結果之舒適性評估139
6.9 小結139

第七章 結論與建議175
7.1 結論175
7.2 建議177

參考文獻179

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