坡面薄层水流优势流速研究

发布时间：2018-08-15 14:45

【摘要】：降雨形成的径流是产生坡面土壤侵蚀的主要动力来源,径流流速是土壤侵蚀模型的重要参数之一。为研究电解质示踪法测量坡面水流流速过程中电解质优势流速和水流流速的关系,本研究利用实验水槽,在坡度4°、8°、12°,流量12、24、48 L/min条件下,于距离电解质注入位置0.3、0.6、0.9、1.2、1.5 m处放置探针测量电解质传递过程,计算不同工况下各测量断面的电解质优势流速。结果表明:流量对电解质优势流速的影响大于坡度对其影响,电解质优势流速随距离增加而增大,采用指数函数拟合计算得到的电解质优势流速随距离的变化过程,得到稳定的电解质优势流速,即水流优势流速,其范围在0.241~0.568 m/s之间。随坡度和流量的增大,水流优势流速均增大。流量对水流优势流速增长的影响大于坡度对其的影响。不同坡度和流量条件下,水流优势流速与平均流速基本一致,二者的比值为1.007,水流优势流速与最大流速的比值为0.774,平均流速与最大流速的比值为0.776,符合坡面薄层水流的流态。结果可为研究坡面薄层水流动力过程提供新的计算方法和参考数据。
[Abstract]:Runoff formed by rainfall is the main power source of soil erosion on slope. Runoff velocity is one of the important parameters of soil erosion model. In order to study the relationship between electrolyte dominant velocity and flow velocity in the process of measuring flow velocity on slope surface by electrolyte tracer method, the experimental flume was used in this study under the conditions of 4 掳~ 8 掳~ 12 掳and 12 ~ 2448 L/min flow rate. The electrolyte transfer process was measured with a probe at 1.5 m from the electrolyte injection position of 0.3 ~ 0.6 ~ 0.9 ~ 1.2m, and the electrolyte dominant velocity of the measured sections was calculated under different operating conditions. The results show that the influence of flow rate on the electrolyte dominant velocity is greater than that of the slope, and the electrolyte dominant velocity increases with the increase of the distance. The variation process of the electrolyte dominant velocity with the distance is calculated by exponential function fitting. The stable electrolyte dominant velocity, that is, the dominant current velocity of water flow, was obtained in the range of 0.241 ~ 0.568 m / s. With the increase of slope and flow, the dominant flow velocity increases. The effect of flow rate on the increase of dominant flow velocity is greater than that of slope. Under different slope and discharge conditions, the dominant flow velocity and the average flow velocity are basically the same, the ratio of them is 1.007, the ratio of the dominant velocity to the maximum velocity is 0.774, and the ratio of the average velocity to the maximum velocity is 0.776, which accords with the flow pattern of thin layer flow on the slope. The results can provide a new calculation method and reference data for the study of thin layer hydrodynamic process on slope surface.
【作者单位】：中国农业大学水利与土木工程学院;天津市龙网科技发展有限公司;
【基金】：国家自然科学基金重点项目“高海拔寒区融水土壤侵蚀机理与过程模拟研究”(41230746)
【分类号】：S157.1

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