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標題: 單階滑流之流場特性探討
Study on the Characteristics of Skimming Flow
作者: 周伸鴻
Jhou, Shen-Hung
關鍵字: Skimming Flow;滑流
出版社: 土木工程學系所
引用: 1.Moore, W. L. (1943) “Energy loss at the base of free overfall”, Transactions, ASCE, 108, 1343-1360. 2.Rand, W. (1955) “Flow geometry at straight drop spillways”, Proceedings of the American Society of Civil Engineers, 81, 1-13. 3.Etheridge, D. W., and Kemp, P. H. (1978) “Measurement of turbulent flow downstream of a rearward-facing step”, Journal of Fluid Mechanics, 86, 545-566. 4.Rockwell, D., and Knisely, C. (1979) “The organized nature of flow impingement upon a carner”, Journal of Fluid Mechanics, 93, 413-432. 5.Rajaratnam, N. (1990) “Skimming flow in stepped spillways”, Journal of Hydraulic Engineering, 116, 587-591. 6.Chanson, H. (1994) ”Hydraulics of skimming flows over stepped channels and spillways”, Journal of Hydraulic Research, 32(3) , 445-460. 7.Rajaratnam, N., and Chamani, M. R. (1995) ”Energy loss at drops”, Journal of Hydraulic Research, 33( 3), 373-384. 8.周憲德、黃貴麟 (1996):「階梯式舌流之消能特性」,第八屆水利研討會論文集。 9.Wu, S., and Rajaratnam, N. (1998) ”Impinging jet and surface flow regimes at drop ”, Journal of Hydraulic Research, 36(1), 69-74. 10.孫洪福 (1998):「單階自由跌水流場特性之實驗探討」,國立中興大學土木工程研究所碩士論文。 11.粱文壇 (1998):「跌水迴流區之水理分析」,國立中央大學土木工程研究所碩士論文。 12.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研究所碩士論文。 13.莊仁和 (2000):「自由跌水消能池中週期性振盪流場之特性探討」,國立中興大學土木工程研究所碩士論文。 14.顏清連 (2000):「高速流水理設計」,中興工程科技研究發展基金會。 15.Kuo, C. H., Huang, S. H., Chung, C. W.(2000) “Self-sustained oscillation induced by horizontal cover plate above cavity”, Journal of Fluids and Structures, 14, 25-48. 16.Philip, T., and Roger, K. (2000) ”Hydraulic design of energy dissipators for culverts and channels”, Hydraulic Engineering Circular , 14, Third Edition. 17.Chanson, H. (2001) ”A transition flow regime on stepped spillways : the facts”, Proceeding of the 29th IAHR congress , 490-498. 18.邱泳仁 (2001):「垂直式單階跌水工與跌水消能池之流場特性探討」,國立中興大學土木工程研究所碩士論文。 19.林呈、謝世圳、莊仁合 (2002):「垂直式跌水工靜水池內週期性振盪流場特性之實驗探討」,中國土木水利工程學刊。 20.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研究所碩士論文。 21.Gonzalez, A. (2004) ”Interactions between cavity flow and main stream skimming flow:an experimental study”, Canadian Journal Civic Engineering, 31, 33-44. 22.Lin, C., Hwung, W. Y., Hsieh, S. C., and Chang, K. A. (2007) “Experimental study on mean velocity characteristics of flow over vertical drop”, Journal of Hydraulic Research, 45(1), 33-42. 23.謝世圳 (2008) :「建置具高時間解析之PIV系統並應用於圓柱近域尾流特性之探討」,國立中興大學土木工程研究所博士學位論文(初稿)。 24.Lin, C., Hsieh, S. C., Kuo, K. J., and Chang, K. A. (2008) “Reply to the Discussion : Experimental study on mean velocity characteristics of flow over vertical drop” Journal of Hydraulic Research, 46(3), 425-428.
本研究使用高速PIV量測系統,配合流場可視化,於無因次臨界水深(Yc /H) 範圍為0.335 ~ 0.632之條件下,針對單階滑流進行定性觀察及定量分析。根據定性觀察結果,將流場分成滑動射流區及水墊區,並分別對此兩區域進行速度場之量測與分析。
首先針對滑動射流區,根據數位影像進行水面線判讀及實際量測以驗證之,最後以複回歸分析訂定水面線。為了量測剪力層速度剖面,將直角座標系統轉換為曲線座標系統,依序從上游到下游切出數個剖面。經由量測結果可知,滑動射流區之剪力層厚度隨著愈往下游增厚。使用Lin et al. (2008)剪力層之分析方法,以剪力層中心(Yrc)、剪力層特徵厚度(bs)為長度尺度、以上下層速度(Uu、Ud)為速度尺度,進行無因次分析後,可得相似方程式。

The characteristics of skimming flows over a vertical drop were investigated experimentally using visualization technique and high speed particle image velocimetry (HSPIV) system. The non-dimensional critical depth (Yc/H) ranges from 0.335 to 0.632. According to the result observed qualitatively by using visualization technique, the flow region can be divided to sliding jet and pool regions. The flow fields were measured and discussed for these two regions.
First the study aims at sliding jet. According to digital image and water surface profile measured by point gauge, the curve of water surface can be determined by multi-variable regression. In order to measure the velocity of shear layer, curvilinear coordinate used instead of cartesian coordinate. The velocity profiles were measured from upstream to downstream. Based on the result, the shear layer thickness increases as the sliding jet moves downstream. Using the method proposed by Lin et al. (2008), the velocity profiles can be established by the center point of shear layer, Yrc, the specific width, bs, as length scale and the velocities of the upper and lower boundary of specific width Uu and Ud, as velocity scale., the similarity profile of shear layer was obtained as following:(略)
The study also focuses on the characteristics of pool region. The shape of velocity profiles in the pool is similar to a wall jet. Different characteristic values were tested for velocity and length scales for similarity analysis. Finally, by selecting the maximum adverse velocity Um as velocity scale and half-width thickness b0 as length scale, similarity profile can be obtained in the form of:(略)
其他識別: U0005-2908200816535500
Appears in Collections:土木工程學系所

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