Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/89438
標題: Experimental Study on Flows Induced Scour around Vegetation Patch with Different Densities
水流通過不同密度植生群周圍沖刷之試驗研究
作者: 黃泰然
Tai-Jan Huang
關鍵字: 試驗;渠槽;雙密度植生;沖刷;experiment;flume test;dual-density vegetation;scour
引用: 參考文獻 1. 楊克君,劉興年,槽叔尤,張之湘,2006,「植被作用下的复式河槽漫灘水流紊動特性」,水利學報,36(10): 1263-1268。 2. 吳沛倫,2001,「不均勻橋墩及群樁基礎之局部沖刷研究」,國立中央大學土木工程研究所碩士論文。 3. 嚴曉嘉,2007,「植生擺設型態水流與床砂變化之渠槽實驗」,國立中興大學水土保持學系研究所碩士論文。 4. 柯柏睿,2014,「剛性非浸沒植生群周圍流場及底床沖淤之試驗研究」,國立中興大學水土保持學系研究所碩士論文。 5. 財団法人整備編,1999,「河川 樹木管理手引 河川区域内樹木伐採・ 植樹基準解説」,山海堂。 6. Bennett, S. J., Pirim, T., & Barkdoll, B. D., (2002), 'Using simulated emergent vegetation to alter stream flow direction within a straight experimental channel,'Geomorphology, 44(1): 115-126. 7. Brookes, A., & Shields, F. D. (Eds.)., (1996), 'River channel restoration: guiding principles for sustainable projects,' Chichester: Wiley: 433. 8. Chen, Z., Ortiz, A., Zong, L., & Nepf, H., (2012), 'The wake structure behind a porous obstruction and its implications for deposition near a finite patch of emergent vegetation,' Water Resources Research, 48(9): WR012224. 9. Darby S. E., (1999), 'Effect of Riparian Vegetation on Flow Resistance and Flood Potential,' Journal of Hydraulic Engineering, Volume 125(5): 443-454. 10. Dey, S., & Sarkar, A., (2006), 'Scour downstream of an apron due to submerged horizontal jets,' Journal of hydraulic engineering, 132(3): 246-257. 11. Elliott, A.H., (2000), 'Settling of Fine Sediment In A Channel with Emergent Vegetation,' Journal of hydraulic engineering: 570-577. 12. Follett E. M. and Nepf H. M., (2012)., 'Sediment patterns near a model patch of reedy emergent vegetation,' Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Geomorphology, 179: 141-151. 13. Ghisalberti, M., & Nepf, H. M., (2002), 'Mixing layers and coherent structures in vegetated aquatic flows,' Journal of Geophysical Research: Oceans (1978–2012), 107(C2): 1-11. 14. Hongwu, T., Wang, H., Liang, D. F., Lv, S. Q., & Yan, L., (2013), 'Incipient motion of sediment in the presence of emergent rigid vegetation,'Journal of Hydro-environment Research, 7(3): 202-208. 15. Järvelä J. (2002), 'Flow resistance of flexible and stiff vegetation: a flume study with natural plants,' Journal of Hydrology, Volume 269, Issues 1-2(1): 44-54. 16. James, C. S., Birkhead, A. L., Jordanova, A. A., & O'sullivan, J. J., (2004),'Flow resistance of emergent vegetation,'Journal of Hydraulic Research, 42(4): 390-398. 17. Jin, R., Cao, Y., Mirkin, C. A., Kelly, K. L., Schatz, G. C., & Zheng, J. G., (2001), 'Photoinduced conversion of silver nanospheres to nanoprisms, ' Science, 294(5548): 1901-1903. 18. Kouwen, N., and Fathi-Moghadam, M., (2000), 'Friction Factors for ConiferousTrees along Rivers,' Journal of Hydraulic Engineering, 12(10): 732-740. 19. Kuhnle, Roger A., Carlos V. Alonso, and F. Douglas Shields Jr., (2002), 'Local scour associated with angled spur dikes,' Journal of Hydraulic Engineering 128(12): 1087-1093. 20. Melville, B. W., and Chiew, Y. M., (1999), 'Time scale for local scour at bridge piers,' Journal of the Hydraulics Engineering, Volume 125: 59-65. 21. Nepf, H. M., (1999), 'Drag, turbulence, and diffusion in flow through emergent vegetation,' Water resources research, 35(2): 479-489. 22. Rahman, M., Murata, H., Nagata, N., & Muramoto, Y., (1998), 'Local scour around spur-dike-like structures and their countermeasures using sacrificial piles,' 水工學論文集, 42: 991-996. 23. Tsujimoto, T., (2000), 'Fluvial processes in streams with vegetation,' J. Hydraulic Res., 37(6): 789-803. 24. Wu, F. C., Shen, H. W., & Chou, Y. J., (1999), 'Variation of roughness coefficients for unsubmerged and submerged vegetation,' Journal of Hydraulic Engineering, 125(9): 934-942.
摘要: 
天然河道中,當水流經過時,會因為兩岸植生生長茂密受到阻擋通水面積減小,造成底床型態產生變化,底床之沖刷與淤積改變會影響河道的穩定性,以往研究關於植生造成底床沖淤影響多以單密度植生群作探討,本研究延續柯(2014)單密度植生試驗加以擴展,把密度範圍做得更廣,並加入複合式密度加以探討,模擬高莖植物在高灘地對河床的沖淤影響,比較不同密度模型植生對底床沖淤影響差異。
考量植物通常沿兩岸生長,試驗過程將植生配置於渠槽之單側邊壁,試驗流速為趨近泥砂起動之流速,底床之平衡型態以雷射測距儀量測,試驗植生單密度設計為0.04、0.07、0.15、0.22及0.3,複合式密度為0.03、0.05、0.09及0.12,分析結果顯示單一密度0.03到0.12時,無因次化的沖刷坑的影響長度D變化範圍介於1.30-1.50,無因次化的1/2D時沖刷坑影響寬度B變化範圍介於1.11-1.48,無因次化的堆積丘的寬度E變化範圍介於1.18-1.67,無因次化的堆積丘的長度F變化範圍介於0.49-1.81,且B及E與植生密度相比較成正比,而D與F成反比;複合式密度植生群最大沖刷深度都會發生在密度0.03植生區內,無因次的沖刷坑影響長度範圍變化介於1.38-1.49與植生密度相比較成正比,而無因次的堆積區的影響寬度範圍變化介於0.91-1.22與植生密度相比較成反比。

In the natural rivers, woody vegetation commonly grows along the riverbank. When flows run through the woody vegetation, the stream processes are markedly affected. Most of the previous studies explored the flow or sediment characteristics of single-density vegetation. This study extended the single-density vegetation experiments of Ke (2014) and used combinations of dual-density vegetation for experiments. The flows induced scour around vegetation zone in different density was investigated.
Considering the vegetation grows along the nature bank, the vegetation model is arranged along one side of the flume wall. The experimental flow was steady and flow velocity was adopted to close to the initiation of sediment motion. The bed morphology of equilibrium scour condition was measured by a Laser Distance Meter in the cases of vegetation density equal to 0.04, 0.07, 0.15, 0.22, and 0.3. Test results of dual-density vegetation were made by combinations of vegetation density equal to 0.03, 0.05, 0.09, and 0.12. The vegetation densities were used to examine the effects of the vegetation on the characteristic lengths of the scour hole. In the single density ranging from 0.03 to 0.12, the dimensionless scour length (D) ranges between 1.30-1.50, the dimensionless scour width (B) ranges between 1.11-1.48, the dimensionless accumulation width (E) ranges between 1.18-1.67, and the dimensionless accumulation length (F) ranges between 0.49-1.81. Moreover, B and E are found to be proportional to the vegetation density, and the D and F are inversely proportional to the vegetation density. In the experiments of dual-density vegetation, the maximum scour depths are located in the areas with vegetation density equal to 0.03. The dimensionless scour length ranges between 1.38-1.49 and it is also proportional to the vegetation density. The dimensionless accumulation width ranges between 0.91-1.22 and that is inversely proportional to the vegetation density.
URI: http://hdl.handle.net/11455/89438
其他識別: U0005-1908201514470500
Rights: 同意授權瀏覽/列印電子全文服務,2018-08-21起公開。
Appears in Collections:水土保持學系

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