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標題: 單階自由跌水作用下坡度渠床沖擊特性之試驗研究
Hydraulic Characteristics of Flow over Sloping Bed Impacted by the Free Overfall
作者: 張幀禎
Chang, Chen-Chen
關鍵字: free overfall;自由跌水;bed slope;pressure head distribution;渠床坡度;壓力水頭分佈
出版社: 土木工程學系所
引用: 1. 宋爾寧(1999),「帶工法對投潭水流行為及沖刷特性之影響」,國立中興大學土木工程學系,碩士論文。 2. 李秉融(2003),「單階自由跌水於不同尾水位之流場特性探討」,國立中興大學土木工程學系,碩士論文。 3. 林 呈、莊仁合、謝世圳(2002),「垂直式跌水工靜水池內週期性振盪流特性之實驗探討」,中國土木水利工程學刊,第15卷,第1期,pp.107-124。 4. 林 呈、黃文彥、顏光輝(1999),「自由跌水之舌流區內速度場的量測探討」,第11屆水利工程研討會論文集,pp.J35-J43。 5. 梁文壇(1998),「跌水迴水區之水理分析」,國立中央大學土木工程學系,碩士論文。 6. 陳正炎(1987),「投潭水作用下渠床沖刷剖面之研究」,台灣水利,第35卷,第1期,pp.35-52。 7. 陳正炎、郭信成、鐘文傳(1993),「堰壩投潭沖刷特性因子之研究」,中華水土保持學報,第24卷,第2期,pp.18-89。 8. 陳正炎、郭信成(1994),「堰壩投潭之沖刷坑特性及其坡度效應研究」,第7屆水利工程研討會論文集,pp.B263-B274。 9. 陳正炎、陳聖文、林宏宇(2000),「帶工法對投潭水流沖刷特性之研究」,興大工程學刊,第11卷,第3期,pp.1-13。 10. 陳正炎、彭思顯、鐘文傳(1994),「投潭水作用下局部沖刷之沖刷率研究」,中華水土保持學報,第25卷,第3期,pp.135-142。 11. 陳正炎、蔡建文(1995),「堰壩投潭水流沖擊力之研究」,中華水土保持學報,第26卷,第2期,pp.135-144。 12. 陳聖文(2000),「防砂壩下游帶工佈置之試驗研究」,國立中興大學土木學系,碩士論文。 13. 黃文彥(1999),「單階自由跌水之速度場量測與分析」,國立中興大學土木工程學系,碩士論文。 14. 蘇重光(1990),「貼面水舌影響水工結構物下游河床承受衝擊力之研究」,行政院國家科學委員會研究計畫報告。 15. 蘇重光、連惠邦(1993),「防砂壩下游天然河床受壩頂溢流沖刷之研究」,台灣水利,第41卷,第2期,pp.35-41。 16. Chanson, H.(1995), “Hydraulic design of stepped cascades, channels, weirs and spillways,” Pergamon , Oxford, UK, pp.292. 17. Davis, A. C., Ellett, B. G. S., and Jacob, R. P.(1999), “Estimating trajectory of free overfall nappe,” Journal of Hydraulic Engineering, ASCE, Vol.125, No.1, pp.79-82. 18. Farhoudi, J. and Smith, K. V. H.(1985), “Local scour profiles downstream of hydraulic jump,” Journal of Hydraulic Engineering, ASCE, Vol.23, No.4, pp.343-358. 19. Hoffmans, G. J. C. M.(1998), “Jet scour in equilibrium phase,” Journal of Hydraulic Engineering, ASCE, Vol.124, No.4, pp.430-436. 20. Hager, W. H.(1983), “Hydraulics of plane free overfall,” Journal of Hydraulic Engineering, ASCE, Vol.109, No.12, pp.1683-1697. 21. Ippen, P. J.(1943), ”Engineering hydraulic,“ John Wiely and Sons, Inc., New York, pp.570. 22. Mason, P. J. and Arumugam, K.(1985), “Free jet scour below dams and flip buckets,” Journal of Hydraulic Engineering, ASCE, Vol.111, No.2, pp.220-235. 23. Moore, W. L.(1943), “Energy loss at the base of a free over-fall,” Transactions, ASCE, Vol.108, pp.1343-1360. 24. Rajaratnam, N. and Chamani, M. R.(1995), “Energy loss at drop,” Journal of Hydraulic Reserch, IAHR, Vol.33, No.3, pp.373-384. 25. Rand, W.(1955), “Flow geometry at straight drop spillways,” Journal of Hydraulic Engineering, ASCE, Vol.81, pp.1-13. 26. Rouse, H.(1936), “Discharge characteristics of the free overfall,” Civil Engineering, ASCE, Vol.6, No.4, pp.257-260. 27. White, M. P.(1943), “Discussion on energy loss of free over-fall,” Transactions, ASCE, Vol.108, pp.1361-1364.
本研究藉由室內渠槽試驗,進行定量清水流及針對不同渠床坡度S (=0~9%)、不同跌水高度H(=0.15~0.30 m)進行單階自由跌水試驗,且在自由跌水沖擊下游處設置不干擾流場之壓力量測系統。經由資料擷取器所輸出之訊號進行處理,測定下游縱向之渠床壓力水頭分佈。試驗結果發現所獲致之自由跌水最大沖擊壓力水頭(Hpd)、水流沖擊位置(Ld)及單寬沖擊力(Fd)與跌水數(D)呈正相關,與坡度(S)亦為正相關;水墊區水深(Yp)則與跌水數(D)呈正相關,與坡度(S)為負相關;能量損失( )與跌水數(D)呈負相關,與坡度(S)為正相關;水流沖擊角度(θ)與跌水數(D)呈負相關,亦與坡度(S)為負相關。

In recent years, single-stage free overfall flow have been widely used in hydraulic structures. The impact force of a free-falling nappe is quite large and the point where the nappe plunges into the tailwater is the weakest position of the drop energy structure. Previous studies focus mostly on the energy dissipation relationship between the upper and lower streams, and the internal variations of the flow field. Only few of them investigated the nappe impact forces on the river beds. According to statistics of the 60 largest rivers in Taiwan, there are 43 rivers (72 percent of the 60 rivers) with average slope less than 7 percent. It is worth studying the impact characteristics and their relationships to channel bed slope.
This study carries out a series of indoor channel experiments of single-stage free overfall flows with clear water under steady flow conditions for various downstream bed slopes (S =0~9%) and various drop heights (H =0.15~0.30 m). The longitudinal pressure head distribution along the downstream channel bed was measured by way of taking readings from a set of pressure transducer system, which doesn't disturb the existing flow field. The experimental results indicate that the maximum impact pressure (Hpd), the impact position (Ld) and the unit width of the impact force (Fd) appear to be proportional to the drop number (D) and the bed slope of the downstream channel (S). The depth of the tailwater pool (Yp) is proportional to D but it is inversely proportional to S. The energy loss ( ) is inversely proportional to D but it is proportional to S. The nappe impact angle (θ ) is inversely proportional to both D and S.
其他識別: U0005-2907200813382700
Appears in Collections:土木工程學系所

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