坡面薄层水流水动力学特性试验

坡面流水动学特性对阐明土壤侵蚀和坡面产沙机理均有重要意义，采用坡面定床阻力试验，定量研究了6种不同粗糙度床面、5种不同坡度下坡面薄层水流水力要素关系及阻力的变化特征，以期揭示坡面薄层水流阻力的内在规律性。结果表明，坡面薄层水流流态指数随坡度呈现出的先减小后增加的变化趋势，当试验坡度小于0.15 rad时，流态指数随坡度的增加而逐渐减小，当坡度大于0.15 rad时，出现相反的变化趋势。流态指数随床面粗糙度呈抛物线变化趋势，其均值为0.376，总体上坡面薄层水流属于滚波流区和过渡流区的范畴；水流弗劳德数与单宽流量和试验坡度均成幂函数关系，临界流对应的单宽流量随粗糙度的增加而增大，随坡度的增加而减...

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Bibliographic Details
Published in农业工程学报 Vol. 30; no. 15; pp. 182 - 189
Main Author 张宽地 王光谦 孙晓敏 杨帆 吕宏兴
Format Journal Article
LanguageChinese
Published 西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室，杨凌 712100 2014
西北农林科技大学水利与建筑工程学院，杨凌 712100%清华大学水利系,北京,100084%西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室,杨凌,712100%西北农林科技大学水利与建筑工程学院,杨凌,712100
Subjects
力学性能
坡面薄层水流
水动力学
流态
试验
阻力系数
力学性能
坡面薄层水流
阻力系数
试验
experiments
shallow open channel flow on slope
hydrodynamics
resistance coefficient
流态
flow regime
mechanical properties
水动力学
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ISSN1002-6819
DOI10.3969/j.issn.1002-6819.2014.15.024

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Summary:坡面流水动学特性对阐明土壤侵蚀和坡面产沙机理均有重要意义，采用坡面定床阻力试验，定量研究了6种不同粗糙度床面、5种不同坡度下坡面薄层水流水力要素关系及阻力的变化特征，以期揭示坡面薄层水流阻力的内在规律性。结果表明，坡面薄层水流流态指数随坡度呈现出的先减小后增加的变化趋势，当试验坡度小于0.15 rad时，流态指数随坡度的增加而逐渐减小，当坡度大于0.15 rad时，出现相反的变化趋势。流态指数随床面粗糙度呈抛物线变化趋势，其均值为0.376，总体上坡面薄层水流属于滚波流区和过渡流区的范畴；水流弗劳德数与单宽流量和试验坡度均成幂函数关系，临界流对应的单宽流量随粗糙度的增加而增大，随坡度的增加而减小，水流流型处于临界流和急流型态；阻力系数与单宽流量呈幂函数关系，而与雷诺数成反比关系，关于增阻的原因主要与绕流产生压差阻力和坡面滚波流引起的局部阻力有关，并根据薄层水流阻力特征，提出了滚波流区阻力计算公式。研究成果可为坡面土壤侵蚀预报模型构建提供理论依据，从而促进明渠水流理论向坡面水流方面扩展。
Bibliography:Hydraulic characteristics of overland flow are of importance in elucidating the mechanisms of soil erosion and sediment yield on slope. By a fixed-bed resistance experiment, the relationship of hydraulic parameters and the resistance characteristics for the shallow flow are quantitatively studied under conditions of six roughness beds and five gradients. Results showed that the index of the shallow flow regime exhibited a saddle-shape changing trend with increased gradient. The index of the shallow flow regime would gradually decrease with the increase of gradient when the gradient was less than 0.15 rad, but the trend was opposite when the gradient was higher than 0.15 rad. The index of the shallow flow regime presented a parabolic changing trend with increasing roughness, and the average index was 0.367. For the bed roughness less than 0.38, the flow range per unit width in unstable flow region became narrower with the increase of roughness, and the flow extended to the transitional zone;For the bed roughne
ISSN:1002-6819
DOI:10.3969/j.issn.1002-6819.2014.15.024