文章摘要
张红武,张罗号,彭昊,蔡蓉蓉.冲积河流糙率由来与计算方法研究[J].水利学报,2020,51(7):774-787
冲积河流糙率由来与计算方法研究
Research on cognition and calculation method of alluvial river roughness
投稿时间:2020-03-03  
DOI:10.13243/j.cnki.slxb.20200130
中文关键词: 糙率  冲积河流  水流阻力  计算方法  黄河  弗劳德数
英文关键词: roughness  alluvial river  flow resistance  calculation method  Yellow River  Froude number
基金项目:国家重点研发计划项目(2016YFC0402500)
作者单位E-mail
张红武 清华大学 水沙科学与水利水电工程国家重点实验室, 北京 100084  
张罗号 河海大学 水利水电学院, 江苏 南京 210098 zlh678@aliyun.com 
彭昊 中国科学院 地理科学与资源研究所, 北京 100101  
蔡蓉蓉 清华大学 水沙科学与水利水电工程国家重点实验室, 北京 100084  
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中文摘要:
      为在水力学及河流学科教学与研究中减少误解,本文在系统回顾了前人明渠流速计算公式研究成就的艰辛过程中,指出教科书与文献存在的误解;并在述评糙率公式优缺点后,指出了现有方法存在的问题。认为在曼宁水流阻力公式是纯经验公式和糙率测验精度实难保证的状况下,且今后相当长时期内人们尚难科学描述沙波兴衰机理及沙粒沙波阻力转换关系,给出糙率理论公式很不现实;建立实用性公式需抓住Fr这个同其他判别沙波运动状态的参数有关联性与可替代性的首要参数;构建出可适应模型试验反映的“nFr增大而减小,Fr很小时n会较大”变化趋势的公式形式后,根据冲积河流“糙率最大值一般为糙率较小值的10倍”的实际情况与“Fr=0.5时糙率接近动平床糙率”的动床模型试验结果,确定待定系数与参考糙率,建立了糙率简便公式(21)。为提高公式精度和适用范围,以沙粒阻力因子反映沙粒肤面阻力作用,遂给出体现沙粒肤面摩擦影响的动床糙率公式(22),并通过引入浑水卡门常数适当考虑含沙量对水流能耗的影响,进一步给出了考虑床面沙粒与含沙量共同影响的糙率计算公式(23)。大量冲积河流实测资料系统验证表明,本文建立的糙率公式明显比现有公式更符合实际。
英文摘要:
      The paper systematically reviewed the research on the calculation of open channel velocity, point out the misunderstanding of literature. After reviewing the advantages and disadvantages of the rough-ness formula, the problems of the existing methods are pointed out. It is considered that under the situa-tion that the Manning formula is a pure empirical formula and the accuracy of the roughness test is diffi-cult to guarantee. It is difficult to describe the mechanism of sand wave fluctuation and the relationship be-tween sand particles and sand wave resistance. The key to establishing a practical formula is to introduce Froude number, the primary parameter that is relevant to the determination of the state of sand wave mo-tion. After establishing the formula of the variation law of n with Froude number through model tests, the undetermined coefficient and reference roughness are determined based on the measured data of the alluvial river and the model test results, and a simple formula for the roughness is given. In order to improve the accuracy and applicability of the formula, the sand resistance factor is introduced to establish the rough-ness formula that reflects the sand surface friction, and the Von Kármán constant is introduced to consider the effect of sediment concentration on flow energy consumption, the general roughness formula is obtained. Validation shows that the two roughness formulas established are in good agreement with a large number of measured river data.
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