| 冰盖下矩形河道的综合糙率 |
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| 引用本文： | 陈刚,张玉蓉,周密,顾世祥.冰盖下矩形河道的综合糙率[J].水科学进展,2016,27(2):290-298. |
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| 作者姓名： | 陈刚 张玉蓉 周密 顾世祥 |
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| 作者单位： | 1.河海大学水文水资源与水利工程科学国家重点实验室, 江苏南京 210098; |
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| 基金项目： | 国家水体污染控制与治理科技重大专项(2013ZX07102-006);云南省技术创新人才计划(2011CI092) |
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| 摘 要： | 综合糙率是采用曼宁公式确定河道水位和流量关系的关键参数。在河道冰封期,冰盖的出现增加了流动的阻力,明流条件下确定的综合糙率不再适用,需要重新估算。基于Einstein阻力划分过流断面的原理,冰盖下矩形河道的过水断面可划分为冰盖区、河床区和边壁区。根据总流的连续性方程,在确定各分区糙率系数、水力半径和断面面积的基础上,提出了冰盖下矩形河道综合糙率的计算公式。采用已有的试验水槽测量数据和天然河道实测资料对公式进行了验证,结果表明:公式计算的综合糙率与实测值吻合较好,与Einstein公式和Sabaneev公式相比,计算精度更高;对于冰封水流,宽浅河道采用分区水深代替水力半径进行简化计算的条件有别于明渠水流,在宽深比大于20时,计算结果才满足精度要求。
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| 关 键 词： | 综合糙率 冰盖水流 双层假定 水力半径分割 |
| 收稿时间： | 2015-10-24 |
Composite roughness of rectangular ice-covered rivers |
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| CHEN Gang,ZHANG Yurong,ZHOU Mi,GU Shixiang.Composite roughness of rectangular ice-covered rivers[J].Advances in Water Science,2016,27(2):290-298. |
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| Authors: | CHEN Gang ZHANG Yurong ZHOU Mi GU Shixiang |
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| Affiliation: | 1.State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China;2.Yunnan Survey and Design Institute of Water Conservancy and Hydropower, Kunming 650021, China |
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| Abstract: | Composite roughness is a crucial parameter in determining the stage-discharge relationship using Manning's formula. Due to the increased resistance resulting from ice cover, a stage-discharge relationship developed in open water is not applicable to the ice-affected reason. This calls for the development of a new stage-discharge relationship. According to the Einstein hydraulic radius separation theory, the flow cross section of a rectangular ice-covered river may be divided into bed, ice and side-wall subsections. Based on the determination of hydraulic radius and sectional area of each flow subsection, this paper presents an analytical solution of composite roughness for flows in rectangular ice-covered rivers. Comparisons of the calculated results with measured data from literature show that the proposed formula does well in predicting the composite roughness of rectangular ice-covered rivers. Compared with Einstein formula and Sabaneev formula, the proposed formula produces more accurate results. For wide ice-covered rivers, if width-depth ratio is greater than 20, hydraulic radius may be considered approximately equivalent to flow depth as a simplification of relatively high precision. |
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| Keywords: | composite roughness ice-covered river two-layer hypothesis hydraulic radius separation |
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