Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/16005
標題: 明渠流通過透水四面體框架之水力特性試驗研究
Laboratory investigation of the characteristics in open channel flow passing through a tetrahedron
作者: 洪士評
Hung, Shih-Ping
關鍵字: FLDV;光纖雷射杜普勒流速儀;grade-control structures;tetrahedron frame;shear stress;固床工;透水四面體框架;剪應力
出版社: 土木工程學系所
引用: 1.台灣省水利局,防洪工程設計手冊,1969。 2.錢寧、萬兆惠,泥沙運動力學,科學出版社,1981。 3.張海燕,河流演變工程學,科學出版社,1990。 4.彌津家久、中川博次、瀨谷和彥、鈴木康弘,開水路粗糙度急變流流速分佈及河床斷應力應答特性,水工學論文集,第34卷,第505-510頁,1990。 5.陳儷娟,以光纖雷射杜普勒測速儀量測淺水明渠流之水力特性,興大土木工程研究所碩士論文,1992。 6.楊翰宗,陡坡光滑明渠流水力特性之研究,中興大學土木工程研究所碩士論文,1998。 7.林呈,跨河構造物防制沖刷之技術與策略研究(應用剛性或柔性攔砂堰作為橋基保護方法之評估探討),行政院公共工程委員會專案研究計畫,1999。 8.涂盛文、許文鴻、劉正琪,多目標離岸潛堤之研究,中華民國第二十一屆海洋工程研討會論文集,1999,第365-372頁 9.杜鳳棋,流體力學 ( 下 ),高立圖書,2000。 10.章平平、張志樂,混凝土四面六邊透水框架在壩下消能設計中的應用,工程實踐與研究,第2期,2001。 11.丁肇隆、鄭智元,框型透水潛堤之消波性實驗分析,台大工程學刊,第82期,第33-40頁,2001。 12.張文捷等人,四面六邊透水框架群用於長江護岸固腳工程實例及設計要點,江西水利科技,第28卷,第1期,2002。 13.周永鋒,光滑明渠紊流流場水力特性之研究,中興大學土木工程研究所碩士論文,2002。 14.唐洪武及肖洋等人,透水框架式四面體水流結構及阻力特性研究,第五屆全國泥沙基本理論學術討論會,2002。 15.洪建豪,三維光滑明渠紊流流場之量測與模擬,中興大學土木工程研究所博士論文,2003。 16.吳龍華、周春天、嚴忠民、王南海,架空率桿件長寬比對四面六邊透水框架群減速促淤效果的影響,水利水運工程學報,第3期,第74-77頁,2003。 17.李若華、王少東、曾甄,穿越四面六邊透水框架群的水流阻力特性試驗研究,中國農村水利水電,第10期,第64-66頁,2005。 18.周根娣、顧正華、高柱、唐洪武,四面六邊透水框架尾流場水力特性,長江科學院院報,第22期,第3卷,第9-12頁,2005。 19.郭耀麒、張耀澤,柔性固床工之破壞機制與保護方式水槽試驗案例研究,經濟部水利署,水利,第16期,第201-210頁,2006。 20.方富民,邊界層理論,中興大學,2007。 21.許榮中,計畫 [ 海岸環境營造計畫總檢討及改善策略研究(1/2) ], 經濟部水利署水利規劃試驗所, 2007 22.Carollo, F.G., Ferro. V., and Termini, D. (2002). “Flow velocity measurements in vegetated channels.”J. Hydraul. Eng., 128(7), 664-673. 23.Nezu, I. and Nakagawa, H. (1993). “Turbulent structures and bursting phenomena over roughness discontinuity in open channel flows.” turbulent structures and related environment in various water flows, Scientific Research Activities p.122-129. 24.Nezu, I. and Nakagawa, H. (1993). “Turbulent in open-channel flows.”, Kyoto University ( in Japan ). 25.Tang, H. W. and Xiao Y. “Study on flow and resistance characteristic on penetrating frame tetrahedron-like,” the second U.S.-China joint workshop on sediment and environmental studies. 26.Temple, D. M. (1986). “Velocity distribution coefficients for grass-lined channels.” J. Hydraul. Eng., 113(2), 193-205. 27.Wu, F. C., Shen, H. W., and Chou, Y. J. (1999). “Variation of roughness coefficients for unsubmerged and submerged vegetation.” J. Hydraul. Eng., 125(9), 934-942. 28.http://www.green.pref.tokushima.jp/suisan/s_dayori/53/53sdayori.html 29.http://www.cweun.com.cn/dayujiang 30.http://met.fzu.edu.cn/cai/sg/sgpics/index.asp
摘要: 
台灣地勢陡峭,颱洪時期水流湍急,經常造成河床劇烈沖淤。工程界常使用鼎塊拋石固床工、階梯式混凝土固床工及蛇籠等水工結構物,藉以減緩河床之劇烈變化。此類工法雖可減緩水流強度,惟國內外工程經驗顯示,剛性且直接阻擋水流之水工結構物,常無法承受洪水強大之破壞力而受損,且衍生固床工與河床交界處產生局部沖刷等問題,故透水四面體框架等「柔性工法」因而誕生,惟其減沖促淤之機制則仍有待更深入之研究。
本研究利用二維光纖雷射杜普勒流速儀 ( 2D-FLDV ) ,於光滑明渠中量測水流經過透水四面體框架附近之流場。除利用量測資料探討基本物理機制外,亦針對浸沒流場進行簡化模式之率定與驗證。試驗中量測之獨立變數包括:渠床坡度、水深高度、垂線位置等,而主要分析項目則為:平均流速剖面、紊流強度、總剪應力及雷諾應力分佈等。
量測資料顯示,於陡坡( S = 1% )與緩坡( S = 0.1% )條件下水流經透水四面體框架擾動後,其緊鄰透水四面體區域之中垂線減速效果顯著。此外,由近床區之總剪應力分佈可知,其具有降低泥砂啟動機率,與減沖促淤之功效。四面體框架上部幾何結構對水流產生劇烈之擾動,且其影響距離約為1.5倍桿件長( L )。本研究參考Carollo等人(2002)之明渠流通過水生植物之流速分佈理論,並加入坡度效應,經量測資料之參數率定,可快速求出緊鄰透水四面體框架下游處之流速剖面,並獲得合理之模擬成果。

Due to the steep topography, rivers in Taiwan usually carry rapid flows during typhoon seasons, which frequently causes severe riverbed deformations. Hydraulic structures such as tetrapods, stepped concrete blocks grade-control structures, and gabions are often adopted to reduce the dramatic riverbed changes. However, engineering practices reveal that the rigid type hydraulic structures may not be able to withstand the destructive power of the flood flows. Also, local scours may occur near the downstream end of the grade-control structures. The flexible type grade-control structures such as the permeable tetrahedron frames therefore invented. Nevertheless, the flow retardation mechanism of the tetrahedron frames still needs to be further clarified.
In this study, a two-dimensional fiber-optic laser Doppler velocimeter (2D-FLDV) was adopted to measure the flow field near a permeable tetrahedron frame. The experiments were conducted in a re-circulating flume with a smooth boundary. The experimental data were used not only to clarify the physical mechanism of the flow retardation caused by the tetrahedron frame, but also to calibrate the simple velocity-profile model under the submerged flow conditions. The measured independent variables include: channel slope, flow depth, measuring section. The distributions of mean velocity, turbulence intensities, Reynolds stress and total shear stress were analyzed.
According to the experimental results, the retardation of velocity just downstream of the tetrahedron frame is significant for both steep (S = 1.0%) and mild channel slopes (S = 0.1%). Furthermore, the distribution of total shear stress near channel bed indicates that the tetrahedron frame may low down the probability of sediment movement and scour, and induce deposition. In the present study, the influencing length of the tetrahedron frame is about 1.5 times the length of unit frame. With proper modifications of Carollo et al.'s (2002) theory for channel flows passing through vegetation, the velocity profile immediately downstream of the tetrahedron frame can be quickly predicted with reasonable accuracy.
URI: http://hdl.handle.net/11455/16005
其他識別: U0005-1808200916410900
Appears in Collections:土木工程學系所

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