• •

### 黄土坡面发育平稳的细沟流水动力学特性

1. 1. 中国科学院地理科学与资源研究所 陆地水循环与地表过程重点实验室,北京 100101
2. 华中农业大学 资源与环境学院,武汉 430070
3. 中国科学院教育部 水土保持与生态环境研究中心 黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西 杨凌 712100
• 出版日期:2014-08-25 发布日期:2014-08-25
• 作者简介:

作者简介:王龙生(1988-),男,山东威海人,硕士生,主要研究方向为坡面土壤侵蚀,E-mail:wlsgogo@163.com

• 基金资助:
国家自然科学基金项目(41271304);中国科学院教育部水土保持与生态环境研究中心黄土高原土壤侵蚀与旱地农业国家重点实验室开放基金项目(K318009902-1315)

### Hydrodynamic characteristics of stable growth-rill flow on loess slopes

Longsheng WANG1,2(), Qiangguo CAI1, Chongfa CAI2, Liying SUN1,3()

1. 1. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
2. College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
3. State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Research Center for Soil and Water Conservation and Eco-environmental Sciences, CAS, Yangling 712100, Shaanxi, China
• Online:2014-08-25 Published:2014-08-25

Abstract:

: Rill erosion is the main way of slope erosion on farmland of the Loess Plateau. Rill erosion on slopes accounts for 70% of the total amount of erosion and plays an important role in soil erosion process on loess hillslopes. It is the beginning of qualitative change in the process of soil erosion. Studies of rill erosion can help control soil erosion on slopes, facilitate the development of agricultural production, and serve as the foundation of study of the development process of soil erosion. Natural rainfall may occur intermittently and rills may go through a second rainfall within a short time period. But studies on the dynamic characteristics of rill flow under these circumstances have been few. This research was carried out in the rainfall simulation lab of the State Key Laboratory of Soil Erosion and Dryland Farming on Loess from March to May 2010. Artificial rainfall was applied on a loess slope at an interval of 24 hours under two rainfall conditions, with the first rain that formed relatively stable rill followed by a light rainfall. The results show that: (1) rill flow velocity was impacted by slope length indistinctively. Average velocity of rill flow on slopes of different lengths was not very different. On the other hand, rill flow velocity was greatly influenced by rill morphology. Compared to 20° slope, rill density of 25° slope was higher, while its flow velocity was lower; (2) shear stress is jointly affected by flow discharge and slope. The Reynolds number and Froude number were significantly associated with flow shear stress-the Reynolds number is positively correlated with flow shear stress, but the Froude number had negative correlation with flow shear stress; (3) As the distance from the top of the hill increases, the Darcy-Weisbach resistance coefficient tends to increase as well. With the same rainfall intensity at the second time, the resistance coefficient of steep slope is higher. This indicates a close relationship between resistance coefficient and runoff and slope. There is a significant positive correlation between resistance coefficient and the Reynolds number. Higher Reynolds number means greater average flow rate and intensity. As a result of increased intensity of water flow, rill morphology is more complex and the flow resistance increases. Although the increased Reynolds number also means that the flow depth is larger, the test results show that the drag coefficient under the condition of steep slope is mainly affected by the velocity of flow.

• S157.1