土壤侵蚀中细沟流的初步分析

细沟中水流速度主要受流量、含沙量和下垫面等因素的影响。在流量不变的条件下 ,通过假定粘滞阻力与流速成正比 ,导出水流的运动学方程 ;以此方程对实验测量结果进行非线性拟合 ,得到了水流速度与时间的关系函数 ,摩擦系数与侵蚀强度的关系式及流体粘滞力与泥沙含量的关系式。这些函数式表明此数学模型在流速较小时是可行的 ;水流速度主要受泥沙含量和坡度的影响 ;坡度越大 ,在开始时速度快速增大 ,但达到稳定流速的时间较长

Elementary Analysis of Rill Flow in Course of Soil Erosion

The determination of the velocity in rill flow is the basis of studying the soil erosion. The velocity of rill flow is influenced by flow discharge, sediment concentration, underlying soil and so on. Under the steady discharge, by assuming the resistance of viscosity is directly proportional to the velocity of flow, the dynamic equation of rill flow is deduced. By nonlinear simulation of the experiment data, we obtained functions between velocity of flow and time, the friction coefficient and erosion intensity, and the viscosity force and sediment concentration in flow. The simulating procedure and results show that the model is feasible when the velocity of flow is lower. Velocity of flow is mainly affected by slope and sediment concentration. When the slope is steeper, the velocity enlarges more quickly, but needs more time to achieve steady value.