有植物明渠阻力特性试验研究
|
摘要
天然明渠中生长植物的现象十分普遍。一方面,植物能够保护土壤,避免水土流失,起到固滩固岸的作用;另一方面,植物增加了河床的阻力,使河道水位升高,水流的平均流速减小,降低了河道的行洪能力。因此,探讨植物对水流阻力的影响在水资源可持续利用,河流的生态修复、管理和河道整治等许多方面有重要的科学和实践意义。
本文在分析一般明渠阻力分割理论的基础上,推导出新的阻力分割计算公式,并以此公式为基础采用水槽实验对有植物明渠的阻力特性进行了研究。
首先,通过分析国外学者已发表的资料,发现了爱因斯坦阻力公式可分别用于明渠边壁与床面的阻力计算,结合连续方程、几何关系推导出一般明渠的阻力计算公式,经验证分析,其计算精度较高,可以满足工程及研究需要。
其次,通过实验分析了植物高度、密度不同时边壁平均切应力、植物阻力的变化。边壁平均切应力随植物高度、密度的增加而减小,且这种减小的趋势会随高度、密度的增加而逐渐减小;植物阻力跟植物的倒伏程度、相对淹没度有关,在流量、植物特性不变的情况下,植物阻力随植物高度、密度的增加而增加。
再次,通过实验结合一般明渠阻力公式分析了植物粗糙度K_(sb)的特性。受水流作用,淹没的柔性植物存在倒伏现象, K_(sb)比植物高度小,当植物高度、密度增加时,与之对应的K_(sb)也跟着增加,且植物高度、密度越大,植物高度与K_(sb)在数值上越接近。经过对试验数据的回归分析,推导出粗糙度K_(sb)的计算式。
最后,结合一般明渠阻力公式和植物粗糙度计算式,推导出植物阻力计算式,经分析表明,该公式的推导较为合理,较好地反映了水槽内床面有植物的水流规律。
It is universal that vegetation grow in open channel. Vegetation can prevent water loss and soil erosion and protect the side bank. But the vegetation increase the resistance of the bed, raise the water level, it can also low the flow of open channel. So studying vegetation influence to flow resistance is of significant science and practice meanings in water resources sustainable utilization, river ecology rehabilitation and river improvement.
In this paper, based on resistance segmentation theory of general open channel, a new calculation formula is derived. And combining with the formula and flume experiment, the resistance characteristic of channel with vegetation is studied.
At first, base on analyze of reliable data, it is found the Einstein logarithmic resistance formula can be used calculating in sidewall and bed flow, then combining with flow continuity equation and geometrical relationship , the resistance formula of open channel is derived. The analysis show that the formula has higher precision and can satisfy a engineering and study requirement.
Secondly,based on the experiment of different vegetation height and density, analyzing the variation of the average wall shear stress and vegetation resistance. With the vegetation height and density increasing, the wall shear stress would decrease, and the tendency is reverse with the variation of vegetation height and density. The vegetation resistance is related to vegetation laid degree and relative submerged degree, at the constant discharge and vegetation character, along with the vegetation height and density increasing, the vegetation resistance would increase.
Thirdly, combining with experiment and resistance formula of open channel, the character of vegetation rough degree K_(sb) was analyzed. Subjecting to the flow acting, submerged flexible vegetation has falling phenomenon, K_(sb) is less than vegetation height, while the vegetation height and density increased,related K_(sb) would increase. And the lager the vegetation height and density, the nearer the numerical value between the vegetation height and K_(sb). By the regression analysis to experimental dates, the formula of rough degree K_(sb) is derived.
Finally based on the resistance formula of open channel and the K_(sb) formula, the formula of vegetation resistance was derived. The analysis of actual measurement show the formula has higher precision and the calculated and measured data has minor relative error.
本文在分析一般明渠阻力分割理论的基础上,推导出新的阻力分割计算公式,并以此公式为基础采用水槽实验对有植物明渠的阻力特性进行了研究。
首先,通过分析国外学者已发表的资料,发现了爱因斯坦阻力公式可分别用于明渠边壁与床面的阻力计算,结合连续方程、几何关系推导出一般明渠的阻力计算公式,经验证分析,其计算精度较高,可以满足工程及研究需要。
其次,通过实验分析了植物高度、密度不同时边壁平均切应力、植物阻力的变化。边壁平均切应力随植物高度、密度的增加而减小,且这种减小的趋势会随高度、密度的增加而逐渐减小;植物阻力跟植物的倒伏程度、相对淹没度有关,在流量、植物特性不变的情况下,植物阻力随植物高度、密度的增加而增加。
再次,通过实验结合一般明渠阻力公式分析了植物粗糙度K_(sb)的特性。受水流作用,淹没的柔性植物存在倒伏现象, K_(sb)比植物高度小,当植物高度、密度增加时,与之对应的K_(sb)也跟着增加,且植物高度、密度越大,植物高度与K_(sb)在数值上越接近。经过对试验数据的回归分析,推导出粗糙度K_(sb)的计算式。
最后,结合一般明渠阻力公式和植物粗糙度计算式,推导出植物阻力计算式,经分析表明,该公式的推导较为合理,较好地反映了水槽内床面有植物的水流规律。
It is universal that vegetation grow in open channel. Vegetation can prevent water loss and soil erosion and protect the side bank. But the vegetation increase the resistance of the bed, raise the water level, it can also low the flow of open channel. So studying vegetation influence to flow resistance is of significant science and practice meanings in water resources sustainable utilization, river ecology rehabilitation and river improvement.
In this paper, based on resistance segmentation theory of general open channel, a new calculation formula is derived. And combining with the formula and flume experiment, the resistance characteristic of channel with vegetation is studied.
At first, base on analyze of reliable data, it is found the Einstein logarithmic resistance formula can be used calculating in sidewall and bed flow, then combining with flow continuity equation and geometrical relationship , the resistance formula of open channel is derived. The analysis show that the formula has higher precision and can satisfy a engineering and study requirement.
Secondly,based on the experiment of different vegetation height and density, analyzing the variation of the average wall shear stress and vegetation resistance. With the vegetation height and density increasing, the wall shear stress would decrease, and the tendency is reverse with the variation of vegetation height and density. The vegetation resistance is related to vegetation laid degree and relative submerged degree, at the constant discharge and vegetation character, along with the vegetation height and density increasing, the vegetation resistance would increase.
Thirdly, combining with experiment and resistance formula of open channel, the character of vegetation rough degree K_(sb) was analyzed. Subjecting to the flow acting, submerged flexible vegetation has falling phenomenon, K_(sb) is less than vegetation height, while the vegetation height and density increased,related K_(sb) would increase. And the lager the vegetation height and density, the nearer the numerical value between the vegetation height and K_(sb). By the regression analysis to experimental dates, the formula of rough degree K_(sb) is derived.
Finally based on the resistance formula of open channel and the K_(sb) formula, the formula of vegetation resistance was derived. The analysis of actual measurement show the formula has higher precision and the calculated and measured data has minor relative error.
引文
[1] 毕慈芬,乔旺林.沙棘柔性坝在砒砂岩地区沟道治理中的试验.沙棘,2000, 13(1):28-34
[2] 黄本胜,赖冠文,邱静.河滩种树对行洪影响试验研究.水动力学研究与进展,1999,14(4):468-474
[3] 黄本胜,赖冠文,程禹平.海堤外滩地种树效果及对行洪影响. 人民珠江,1995,88(3):38-41
[4] 姜乃森,吕秀贞,缪集权.河流与水库阻力问题的研究.见:水利水电科学研究院科学研究论文集. 北京:水利电力出版社,1986,124-129
[5] 李榕.关于影响曼宁粗糙系数 n 的水力因素探讨.水利学报,1989,(12):62-66
[6] 惠遇甲,胡春宏.矩形明槽宽深比和边壁糙率对于流速分布和阻力影响的实验研究.水科学进展,1991,(1):22-30
[7] 王达权.湖南省河渠糙率的研究.水利水电技术,1991,(6):25-30
[8] 邓贤贵,王韦.单站糙率的分析及计算方法.水文,1986,(2):39-45
[9] 王晋军.粗糙床面的阻力特性.水动力学研究与进展,1992,7(2):132-137
[10] 何建京,王惠民.流动型态对曼宁糙率系数的影响研究.水文, 2002,22(6):22-24
[11] 周国栋,刘琼轶,王贵仙等.床沙组成对水流阻力的影响.水动力学研究与进展,2003,18(5):576-583
[12] 杨克君,曹叔尤,刘兴年.复式河槽阻力系数及过流能力计算.水科学进展,2005,16(1):23-26
[13] Chow, V. T., Open-channel Hydraulics, Mcgraw-Hill Book Company, Inc., New York 1959
[14] Simons D B, Al-Shaikh-Ali K S and Li R. Flow Resistance in Cobble and Boul- der Riverbeds. Journal of The Hydraulics Division, 1979, 105(9):477-487
[15] Myers W R C. Flow Resistance in Wide Rectangular Channels. Journal of The Hydraulics Division, 1982, 108(4):471-482
[16] Knight D W, Demetriou J D and Hamed M E. Boundary Shear in Smooth Rect- angular Channels. Journal of Hydraulic Engineering, 1984, 110(4):405-421
[17] Knight D W and Macdonald J A. Hydraulic Resistance of Artificial Strip Roughness. Journal of the Hydraulics Division, 1979, 105(6): 675-689
[18] Knight D W, Macdonald J A. Open Channel Flow With Varying Bed Roughness. Journal of the Hydraulics Division, 1979, 105(9):1167-1183
[19] Nouh M A and Townsend R D. Shear-Stress Distribution in Stable Channel Bends. Journal of the Hydraulics Division, 1979, 105(10):1233-1245
[20] 杨树清. 论矩形明渠流边界切应力分布规律.泥沙研究, 1993,(3):95-103
[21] 黄纪中.明渠断面流速与边壁切应力相关的试验研究.武汉水利水电大学学报,1998,31(5):12-16
[22] 胡旭跃,曾光明,黄国和等.矩形明渠边界平均剪切应力变化规律研究. 泥沙研究,2002,(4):44-45
[23] Hsieh T. Resistance of Cylinder Piers in Open-channel Flow. Hydr Div,1964, 90(1):161-173
[24] Li R M and Shen H W. Effect of Tall Vegetation on Flow and Sediment. Hydr Div, 1973, 99(5):793-814
[25] Dunn C,Lopez F and Garcia M. Mean flow and turbulence in a laboratory channel with simulated vegetation.Civil Engineering Studies Hydra engineering Sesries No 51, Dept of Civil Engrg, Univ of Linois at Urbana-Champaign,1996
[26] Stone B M and Shen H T. Hydraulic Resistance of Flow in Channels with Cylin- drical Roughness. Hydr Engrg, 2002, 128(5):500-506
[27] M Fathi-Maghadam and N Kouwen. Nonrigid Nonsubmerged Vegetative Roug- hness on Floodplaind. Hydr Engrg, 1997, 123(1):51-57
[28] Ree W O and Palmer V J. Flow of Water in Channels Protected by Vegetative Lining. In: U S Dept of Agriculture Soil Conservation Service. Washington D C, 1949, 967
[29] Cheng-lung Chen and M ASCE. Flow Resistance in Broad Shallow Grassed Channels. Hydr. Div. 1976
[30] Wu F C, Shen H W and Chou Y. Variation of Roughness Coefficients for Unsubmerged and Submerged Vegetation. Hydr Engrg,1999, 125(9):934-942
[31] 王忖.有植被的河道水流试验研究:[河海大学硕士学位论文],南京:河海大学环境科学与工程学院, 2003,28-32
[32] 邱秀云, 阿不都外力, 程艳, 等. 植物“柔性坝”对水流的影响试验研究. 水利水电技术, 2003,34(9):62-65
[33] 拉尼亚. 非淹没植物水流特性研究:[河海大学硕士学位论文],南京:河海大学环境科学与工程学院, 2005,59-67
[34] Sylvester Petryk, A M ASCE and George Bosmajian. Analysis of flow through vegetation . Hydr Div, 1975, 11457 (7): 871-883
[35] Freeman G E, Rahmeyer W H and Copeland R R. Determination of Resistance Due to Shrubs and Woody Vegetation. Vicksburg,MS: Techmical Report ERDC/CHL TR-00-25 U S. Army Engineer Research and Development Center, 2000,15-28
[36] Tsihrintzis V A. Variation of Roughness Coefficients for Unsubmergde and Submerged Vegetation. Hydr Engrg. 2001,127(3):239-245
[37] и ф 卡拉谢夫等.河道泄水能力与水草河道径流计算.水利水电快报,2001,22(19):25-28
[38] Fischenich. Resistance Due to vegetation. ERDC TN-EMRRP-SR-07,2000
[39] 拾兵,付强,曹叔尤.植物对明渠水流的影响.西南民族学院院报,1998,4(4): 334-337
[40] 倪汉根, 顾峰峰. 湿地非淹没芦苇水流阻力的试验研究. 水动力学研究与进展, 2005,20(2):167-173
[41] Wilson C A M E, Stoesser T, Bates P D, et al. Open Channel Flow through Different Forms of Submerged Flexible Vegetation. Hydr Engrg, 2003,129 (11):847-857
[42] Carollo F G, Ferro V and Termini D. Flow resistance law in channels with flexible submerged vegetation. Hydr Engrg, 2005, 131(7): 554-564
[43] Jarvela Juha. Affect of submerged flexible vegetation on flow structure and resistance. Journal of Hydrology, 2005, 307(1-4): 233-241
[44] Green J C. Effect of macrophyte spatial variability on channel resistance. J Advances in Water Resources, 2006, 29(3): 426 -438
[45] 钱宁,万兆惠. 泥沙运动力学. 北京:科学出版社,1986,197-198
[46] Camp T R. Discussion determination of Kutter’s n for Serwer Partly Filled. Transaction, 1944, 109
[47] 张瑞瑾、谢鉴衡等.武汉水利电力学院,1988
[48] 钱宁,洪柔嘉,麦乔威等.黄河下游的糙率问题.泥沙研究,1959,(1):1-15
[49] 张书农,唐存本.水槽试验的侧壁影响问题.高等学校自然科学学报,1965,1(4):10
[50] 许光祥.综合阻力与河床几何阻力关系得处理方法与阻力方程组解的存在关系.水力学报,1996,(7)
[51] 胡春宏,惠遇甲.关于明槽水流边壁影响校正方法的研究.见:全国泥沙基本理论研究学术讨论会论文集.北京:中国建筑工业出版社,1992,254-265
[52] Knight D W. Boundary Share in Smouth and Rough channels. J of Hydr Div, 1981, 107(7):839-851
[53] Shiono k and Knight D W. Turbulent open channel flows with variable depth across the channel. J Fluid Mech, 1991, 222:617-646
[54] 胡春宏,吉祖稳.论明渠水流边界剪应力分布规律.见:第二届全国泥沙基本理论研究学术讨论会论文集.北京:中国建筑工业出版社,1995,85-93
[55] Inoue E. on the turbulent structure of airflow within crop canopies. J Meteorol- ogical soc of Japan, 1961,(1):317-346
[56] Stoller J and Lemon E R. Turbulent transfer characteristics of the airstream in and above the vegetative canopies at the earth surface. The Energy Budget atthe earth surface, 1963, 72(9):34-35
[57] Murota A and Fukuhara T. Flow structure in a vegetated open channel.” In: Proc 28th Conf on Hydr Japan Soc of civ Engrs. Tokyo,1984, 225-231
[58] Palmer V J. A method for desingning vegetated waterways .Agric Eng, 1945, 26 (12):516-520
[59] Temple D M. Closure of velocity distribution coefficients for grass linned channel. J Hydr Div, 1987, 113(9):1224-1226
[60] Ursula S, Karl W. Experiments on Hydraulic Roughnesss of Macrophytes. In: Proceeding of Theme B XXIX IAHR Congress. Beijing, 2001, 358-364
[2] 黄本胜,赖冠文,邱静.河滩种树对行洪影响试验研究.水动力学研究与进展,1999,14(4):468-474
[3] 黄本胜,赖冠文,程禹平.海堤外滩地种树效果及对行洪影响. 人民珠江,1995,88(3):38-41
[4] 姜乃森,吕秀贞,缪集权.河流与水库阻力问题的研究.见:水利水电科学研究院科学研究论文集. 北京:水利电力出版社,1986,124-129
[5] 李榕.关于影响曼宁粗糙系数 n 的水力因素探讨.水利学报,1989,(12):62-66
[6] 惠遇甲,胡春宏.矩形明槽宽深比和边壁糙率对于流速分布和阻力影响的实验研究.水科学进展,1991,(1):22-30
[7] 王达权.湖南省河渠糙率的研究.水利水电技术,1991,(6):25-30
[8] 邓贤贵,王韦.单站糙率的分析及计算方法.水文,1986,(2):39-45
[9] 王晋军.粗糙床面的阻力特性.水动力学研究与进展,1992,7(2):132-137
[10] 何建京,王惠民.流动型态对曼宁糙率系数的影响研究.水文, 2002,22(6):22-24
[11] 周国栋,刘琼轶,王贵仙等.床沙组成对水流阻力的影响.水动力学研究与进展,2003,18(5):576-583
[12] 杨克君,曹叔尤,刘兴年.复式河槽阻力系数及过流能力计算.水科学进展,2005,16(1):23-26
[13] Chow, V. T., Open-channel Hydraulics, Mcgraw-Hill Book Company, Inc., New York 1959
[14] Simons D B, Al-Shaikh-Ali K S and Li R. Flow Resistance in Cobble and Boul- der Riverbeds. Journal of The Hydraulics Division, 1979, 105(9):477-487
[15] Myers W R C. Flow Resistance in Wide Rectangular Channels. Journal of The Hydraulics Division, 1982, 108(4):471-482
[16] Knight D W, Demetriou J D and Hamed M E. Boundary Shear in Smooth Rect- angular Channels. Journal of Hydraulic Engineering, 1984, 110(4):405-421
[17] Knight D W and Macdonald J A. Hydraulic Resistance of Artificial Strip Roughness. Journal of the Hydraulics Division, 1979, 105(6): 675-689
[18] Knight D W, Macdonald J A. Open Channel Flow With Varying Bed Roughness. Journal of the Hydraulics Division, 1979, 105(9):1167-1183
[19] Nouh M A and Townsend R D. Shear-Stress Distribution in Stable Channel Bends. Journal of the Hydraulics Division, 1979, 105(10):1233-1245
[20] 杨树清. 论矩形明渠流边界切应力分布规律.泥沙研究, 1993,(3):95-103
[21] 黄纪中.明渠断面流速与边壁切应力相关的试验研究.武汉水利水电大学学报,1998,31(5):12-16
[22] 胡旭跃,曾光明,黄国和等.矩形明渠边界平均剪切应力变化规律研究. 泥沙研究,2002,(4):44-45
[23] Hsieh T. Resistance of Cylinder Piers in Open-channel Flow. Hydr Div,1964, 90(1):161-173
[24] Li R M and Shen H W. Effect of Tall Vegetation on Flow and Sediment. Hydr Div, 1973, 99(5):793-814
[25] Dunn C,Lopez F and Garcia M. Mean flow and turbulence in a laboratory channel with simulated vegetation.Civil Engineering Studies Hydra engineering Sesries No 51, Dept of Civil Engrg, Univ of Linois at Urbana-Champaign,1996
[26] Stone B M and Shen H T. Hydraulic Resistance of Flow in Channels with Cylin- drical Roughness. Hydr Engrg, 2002, 128(5):500-506
[27] M Fathi-Maghadam and N Kouwen. Nonrigid Nonsubmerged Vegetative Roug- hness on Floodplaind. Hydr Engrg, 1997, 123(1):51-57
[28] Ree W O and Palmer V J. Flow of Water in Channels Protected by Vegetative Lining. In: U S Dept of Agriculture Soil Conservation Service. Washington D C, 1949, 967
[29] Cheng-lung Chen and M ASCE. Flow Resistance in Broad Shallow Grassed Channels. Hydr. Div. 1976
[30] Wu F C, Shen H W and Chou Y. Variation of Roughness Coefficients for Unsubmerged and Submerged Vegetation. Hydr Engrg,1999, 125(9):934-942
[31] 王忖.有植被的河道水流试验研究:[河海大学硕士学位论文],南京:河海大学环境科学与工程学院, 2003,28-32
[32] 邱秀云, 阿不都外力, 程艳, 等. 植物“柔性坝”对水流的影响试验研究. 水利水电技术, 2003,34(9):62-65
[33] 拉尼亚. 非淹没植物水流特性研究:[河海大学硕士学位论文],南京:河海大学环境科学与工程学院, 2005,59-67
[34] Sylvester Petryk, A M ASCE and George Bosmajian. Analysis of flow through vegetation . Hydr Div, 1975, 11457 (7): 871-883
[35] Freeman G E, Rahmeyer W H and Copeland R R. Determination of Resistance Due to Shrubs and Woody Vegetation. Vicksburg,MS: Techmical Report ERDC/CHL TR-00-25 U S. Army Engineer Research and Development Center, 2000,15-28
[36] Tsihrintzis V A. Variation of Roughness Coefficients for Unsubmergde and Submerged Vegetation. Hydr Engrg. 2001,127(3):239-245
[37] и ф 卡拉谢夫等.河道泄水能力与水草河道径流计算.水利水电快报,2001,22(19):25-28
[38] Fischenich. Resistance Due to vegetation. ERDC TN-EMRRP-SR-07,2000
[39] 拾兵,付强,曹叔尤.植物对明渠水流的影响.西南民族学院院报,1998,4(4): 334-337
[40] 倪汉根, 顾峰峰. 湿地非淹没芦苇水流阻力的试验研究. 水动力学研究与进展, 2005,20(2):167-173
[41] Wilson C A M E, Stoesser T, Bates P D, et al. Open Channel Flow through Different Forms of Submerged Flexible Vegetation. Hydr Engrg, 2003,129 (11):847-857
[42] Carollo F G, Ferro V and Termini D. Flow resistance law in channels with flexible submerged vegetation. Hydr Engrg, 2005, 131(7): 554-564
[43] Jarvela Juha. Affect of submerged flexible vegetation on flow structure and resistance. Journal of Hydrology, 2005, 307(1-4): 233-241
[44] Green J C. Effect of macrophyte spatial variability on channel resistance. J Advances in Water Resources, 2006, 29(3): 426 -438
[45] 钱宁,万兆惠. 泥沙运动力学. 北京:科学出版社,1986,197-198
[46] Camp T R. Discussion determination of Kutter’s n for Serwer Partly Filled. Transaction, 1944, 109
[47] 张瑞瑾、谢鉴衡等.武汉水利电力学院,1988
[48] 钱宁,洪柔嘉,麦乔威等.黄河下游的糙率问题.泥沙研究,1959,(1):1-15
[49] 张书农,唐存本.水槽试验的侧壁影响问题.高等学校自然科学学报,1965,1(4):10
[50] 许光祥.综合阻力与河床几何阻力关系得处理方法与阻力方程组解的存在关系.水力学报,1996,(7)
[51] 胡春宏,惠遇甲.关于明槽水流边壁影响校正方法的研究.见:全国泥沙基本理论研究学术讨论会论文集.北京:中国建筑工业出版社,1992,254-265
[52] Knight D W. Boundary Share in Smouth and Rough channels. J of Hydr Div, 1981, 107(7):839-851
[53] Shiono k and Knight D W. Turbulent open channel flows with variable depth across the channel. J Fluid Mech, 1991, 222:617-646
[54] 胡春宏,吉祖稳.论明渠水流边界剪应力分布规律.见:第二届全国泥沙基本理论研究学术讨论会论文集.北京:中国建筑工业出版社,1995,85-93
[55] Inoue E. on the turbulent structure of airflow within crop canopies. J Meteorol- ogical soc of Japan, 1961,(1):317-346
[56] Stoller J and Lemon E R. Turbulent transfer characteristics of the airstream in and above the vegetative canopies at the earth surface. The Energy Budget atthe earth surface, 1963, 72(9):34-35
[57] Murota A and Fukuhara T. Flow structure in a vegetated open channel.” In: Proc 28th Conf on Hydr Japan Soc of civ Engrs. Tokyo,1984, 225-231
[58] Palmer V J. A method for desingning vegetated waterways .Agric Eng, 1945, 26 (12):516-520
[59] Temple D M. Closure of velocity distribution coefficients for grass linned channel. J Hydr Div, 1987, 113(9):1224-1226
[60] Ursula S, Karl W. Experiments on Hydraulic Roughnesss of Macrophytes. In: Proceeding of Theme B XXIX IAHR Congress. Beijing, 2001, 358-364