跳到主要內容

臺灣博碩士論文加值系統

(44.192.22.242) 您好!臺灣時間:2021/08/05 12:06
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::

詳目顯示

我願授權國圖
: 
twitterline
研究生:李達銘
研究生(外文):Da-MingLi
論文名稱:地表偏轉風對大氣邊界層內高層結構風場影響之研究
論文名稱(外文):Effects of the twisting aloft wind on the wind fields around a high structure in the atmospheric boundary layer
指導教授:方中方中引用關係
指導教授(外文):Chung Fang
學位類別:碩士
校院名稱:國立成功大學
系所名稱:土木工程學系碩博士班
學門:工程學門
學類:土木工程學類
論文種類:學術論文
論文出版年:2012
畢業學年度:100
語文別:中文
論文頁數:201
中文關鍵詞:大氣邊界層偏轉高層風艾克曼螺旋
外文關鍵詞:Atmospheric boundary layerTwisting aloft windEkman spiral
相關次數:
  • 被引用被引用:0
  • 點閱點閱:140
  • 評分評分:
  • 下載下載:0
  • 收藏至我的研究室書目清單書目收藏:0
本研究使用計算模擬套裝軟體Fluent,以穩態分析探討超高層建築物高度接近大氣邊界層厚度時,科氏力效應引致大氣邊界層風隨著高度水平偏轉,對於結構物造成之風荷載與結構環境風場影響之研究,結構體模型假設為剛體,外形分別為圓柱體、方柱體以及兩者隨高度漸縮斷面之柱體。套裝軟體的驗證則採用二維的暫態分析,模擬方形斷面後方的渦流逸散頻率,計算求得的史徹荷數與文獻中的實驗及數值模擬結果接近,以證明Fluent在數值模擬上的可靠性。

數值模擬的結果顯示,地表偏轉風對結構環境風場之影響,在結構體為圓柱體時,環境風場會隨著地表偏轉風的方向改變,並使穩態風場保持對稱;但結構體為方柱體時,穩態風場隨高度偏轉後不再保持對稱,且尾流區隨著高度增加致使範圍擴大,此外,兩者在漸縮斷面下均可抑制結構上部尾流區之範圍。地表偏轉風對結構體因風阻引致合力與合力矩,在模型為圓柱體結構下,會使順風向風阻合力略為降低,而原本趨近於零之側風向風阻合力因地表偏轉風的影響,約提升至順風向總合力的50%,且對結構體受風阻引致合力矩之影響更甚;在模型為方柱體時,結構體所受之合力與合力矩無論在順風向或側風向,均明顯高於圓柱體結構之結果,此外,漸縮斷面的設計可減抑兩者因風阻引致順風向與側風向之合力矩;風阻引致扭矩在四種模型中,均遠小於順風向與側風向之合力矩,可忽略結構體受風阻引致扭矩之效應。故根據研究結果,地表偏轉風對超高層建築物造成之側風向影響不可忽略,且漸縮斷面之圓柱體結構較適合做為超高層建築物之外型。

The wind fields around high-altitude structures inside the atmospheric boundary layer and the induced dynamic loads in the structures are investigated by using the numerical simulations based on the Fluent package, in which the focus is on the twisting effects of winds caused by the Coriolis force. The structure models employed in the numerical simulations are rigid, cylindrical and square columns with/without shrinking cross-sections with altitude. A number of test simulations have been carried out to identify the shedding frequency and the Strohal number of the ka ̀eman ̀ vortex sheet behind a square column, on which the accuracy of the numerical model has been verified.

Results of the numerical simulations are discussed in the following three categories.

(1)The steady-state wind fields around a cylindrical column remain symmetrical along the incoming wind direction, which shifts its orientation gradually to the right due to the Coriolis force, as the altitude increases. On the contrary, such a situation does not prevail for square columns: the wake region increases as the altitude increases. For cylindrical/square columns with shrinking cross-sections with altitude, the wake regions near the top of the columns are reduced significantly.

(2)When compared to the along/cross wind drags on the cylindrical column from no-twisting incoming winds, the induced along-wind drag due to the twisting aloft wind is nearly the same as before, however, the cross-wind drag increases to about 50% of the along-wind drag. In the cases of square columns, the induced along/cross wind drags are much higher than their counterparts for cylindrical columns.

(3)The wind-induced torques on the cylindrical/square columns are much smaller than the drags, either in the along-wind or cross-wind directions. Moreover, it is shown that the drags and torques can be significantly reduced for columns with shrinking cross-sections with altitude.

In summary, the effects induced by the twisting aloft wind due to the Coriolis force should be taken into account for high-altitude structures inside the atmospheric boundary layer. Column with shrinking cross-sections provide an alternative design for high altitude structures with smaller along/cross-wind drags and base torques.

目錄

摘要----------------------------------------------------------------------------------------------- i
Abstract------------------------------------------------------------------------------------------- ii
誌謝----------------------------------------------------------------------------------------------- iii
表目錄-------------------------------------------------------------------------------------------- vi
圖目錄-------------------------------------------------------------------------------------------- vii
符號說明----------------------------------------------------------------------------------------- xv

第一章 風工程概論-------------------------------------------------------------------------- 1
1.1 風工程概述------------------------------------------------------------------- 1
1.2 研究動機---------------------------------------------------------------------- 15
1.3 論文架構與大綱------------------------------------------------------------- 16

第二章 大氣運動方程式-------------------------------------------------------------------- 17
2.1 大氣運動流體力學---------------------------------------------------------- 17
2.2 高層風(Aloft winds) -------------------------------------------------------- 18
2.3 地表風(Surface winds) ----------------------------------------------------- 21
2.4 紊流效應---------------------------------------------------------------------- 24
2.5 超高層結構面臨的風速分佈---------------------------------------------- 26

第三章 計算模擬套裝軟體----------------------------------------------------------------- 29
3.1 ANSYS Workbench操作簡介---------------------------------------------- 29
3.2 計算流體力學簡介---------------------------------------------------------- 33
3.3 Fluent分析介紹-------------------------------------------------------------- 34
3.3.1 幾何建模---------------------------------------------------------------- 35
3.3.2 劃分網格---------------------------------------------------------------- 36
3.3.3 前處理------------------------------------------------------------------- 40
3.3.4 求解計算---------------------------------------------------------------- 44
3.3.5 後處理------------------------------------------------------------------- 48

第四章 數值模擬與結果表示-------------------------------------------------------------- 52
4.1 數值模擬軟體驗證---------------------------------------------------------- 52
4.2 問題定義---------------------------------------------------------------------- 56
4.2.1 計算流體力學簡介---------------------------------------------------- 56
4.2.2 入口平均風速垂向分佈---------------------------------------------- 57
4.2.3 受科氏力影響之入口風速------------------------------------------- 58
4.3 邊界條件設定(Boundary conditions)------------------------------------- 58
4.3.1 計算域與網格劃分---------------------------------------------------- 61
4.3.2 邊界條件與數值模型------------------------------------------------- 65
4.3.3 前處理(Setup)----------------------------------------------------------- 70
4.4 結果與討論------------------------------------------------------------------- 72
4.4.1 結構風場與結構表面風壓------------------------------------------- 72
4.4.2 風阻合力與力矩------------------------------------------------------- 75

第五章 結論與未來展望-------------------------------------------------------------------- 79
5.1 結論---------------------------------------------------------------------------- 79
5.2 未來展望---------------------------------------------------------------------- 80

參考文獻----------------------------------------------------------------------------------------- 81

附錄A-------------------------------------------------------------------------------------------- 83
附錄B-------------------------------------------------------------------------------------------- 187

[1]朱佳仁,風工程概論,科技圖書,台北市,2006。
[2]L. Cochran, R. Derickson, A physical modeler’s view of computational wind engineering, Journal of Wind Engineering and Industrial Aerodynamics , 99, 139-153, 2011.
[3]http://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge_%281940%29, 訪問時間:2012.07.02.
[4]E. Simiu, R. H. Scanlan, Wind Effects in Structure:Fundamentals and Applications to Design, John Wiley, New York, 1996.
[5]P. Bradshaw, Turbulence, Springer, New York, 1978.
[6]H. Liu, Wind Engineering:A Handbook for Structural Engineers, Prentice-Hall, New Jersey, 1991.
[7]C. D. Ahrens, Meteorology Today:An Introduction to Weather, Climate, and the Environment, Thomson/Brooks Cole, Australia, 2007.
[8]方中,極端氣候下之結構工程導論,國立成功大學土木工程學系,上課資料,2010.
[9]謝紹松, 張敬昌, 台北101塔樓結構設計, 永竣工程, 台北市, 2004.
[10]林世陞,「高樓結構裝設調和液柱阻尼減振效應之風洞實驗研究」,國立中央大學土木工程學系碩士論文,2000。
[11]http://en.wikipedia.org/wiki/%E5%8F%B0%E5%8C%97101, 訪問時間:2012.07.02.
[12]內政部,建築物耐風設計規範與解說,2006。
[13]http://www.cv.ncu.edu.tw/html/IIS/ecce/W01/index.htm, 訪問時間:2012.07.02.
[14]http://www.skyscrapercenter.com/building.php?building_id=1, 訪問時間:2012.07.02.
[15]R. W. Fox, A. T. McDonald, P. J. Pritchard, Introduction to Fluid Mechanics, John Wiley, New Jersey, 2004.
[16]P. A. Irwin, W. F. Baker, S. Korista, P. A. Weismantle, L. C. Novak, The Burj Dubai tower, Structure Magazine, 48-51, 2006.
[17]P. A. Weismantle, G. L. Smith, M. Sheriff, Burj Dubai:An architectural technical design case study, The Structural Design of Tall and Special Buildings, 16, 335-360, 2007.
[18]P. A. Irwin, W. F. Baker, The Burj Dubai tower wind engineering, Structural Magazine, 29-31, 2006.
[19]http://www.cadmen.com/Page/Item/Item.aspx?tp=Item&im=13, 訪問時間:2012.07.02.
[20]虎門科技,ANSYS v13 Workbench 基礎訓練課程,上課資料,2010。
[21]楊瑞珍,流體力學計算法,國立成功大學工程科學系,上課資料,2011。
[22]虎門科技,ANSYS Workbench基礎網格處理課程,上課資料,2010。
[23]虎門科技,CFD理論講習課會,上課資料,2010。
[24]D. Bouris, G. Bergeles, 2D LES of vortex shedding from square cylinder, Journal of Wind Engineering and Industrial Aerodynamics, 80, 31-46, 1999.
[25]D. Lyn, S. Einav, W. Rodi, J. Park, A laser doppler velocimetry study of ensemble-averaged characteristics of the turbulent near wake of square cylinder, Journal of Fluid Mechanics, 304, 285-319, 1995.
[26]D. Dura ̃o, M. Heitor, J. Pereira, Measurements of turbulent and periodic flows around a square cross-section cylinder, Experiments in Fluids, 6, 298-304, 1998.
[27]Peter A. Irwin, Wind engineering challenges of the new generation of super-tall buildings, Journal of Wind Engineering and Industrial Aerodynamics, 97, 328-334, 2009.
[28]http://www.skyscrapercenter.com/taipei/taipei-101/, 訪問時間:2012.07.02.
[29]http://www.skyscrapercenter.com/dubai/burj-khalifa/,訪問時間:2012.07.02.
[30]http://www.skyscrapercenter.com/chicago/willis-tower/,訪問時間:2012.07.02.
[31]http://www.skyscrapercenter.com/shanghai/shanghai-world-financial-center/,訪問時間:2012.07.02.
[32]P. J. Richards, R. P. Hoxey, Appropriate boundary conditions for computational wind engineering models using the k-ϵ turbulence model, Journal of Wind Engineering and Industrial Aerodynamics, 46, 145-153, 1993.
[33]D. M. Hargreaves, N. G. Wright, On the use of the k-ϵ model in commercial CFD software to model the neutral atmospheric boundary layer, Journal of Wind Engineering and Industrial Aerodynamics, 95, 355-369, 2007.
[34]方中,流體力學,國立成功大學土木工程學系,上課資料,2008。

連結至畢業學校之論文網頁點我開啟連結
註: 此連結為研究生畢業學校所提供,不一定有電子全文可供下載,若連結有誤,請點選上方之〝勘誤回報〞功能,我們會盡快修正,謝謝!
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top