黄土坡面细沟流水动力学特性  

Dynamics characteristics of rill flow on loess slope

作　　者：董旭[1] 张宽地[1,2] 杨明义[1] 高延良[1] 马小玲[1] 

机构地区：[1]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,陕西杨凌712100 [2]中国科学院水利部水土保持研究所,陕西杨凌712100

出　　处：《中国水土保持科学》2016年第3期45-51,共7页Science of Soil and Water Conservation

基　　金：国家自然科学基金"坡面含沙水流波流耦合特性及泥沙输移机理研究"(51579214);"黄土区坡面水沙过程空间异质性及其尺度效应研究"(51209222);中央高校基本科研业务费专项资金"黄土坡面含沙水流能量耗散规律研究"(Z109021564);黄土高原土壤侵蚀与旱地农业国家重点实验室主任基金"基金超声测量技术研究坡面流流动特性"(A314021402-1619);流域水循环模拟与调控国家重点实验室开放基金"坡面细沟流能量转化研究"(IWHRSKL-2014)

摘　　要：我国是土壤侵蚀最严重的国家之一,黄土高原地区的水土流失造成严重的生态环境恶化问题。为探求黄土细沟流的水动力学特性,从水力学及河流运动力学的角度出发,系统研究6种坡度（2°、4°、6°、8°、10°、12°）,5种流量（8、16、24、32和40 L/min）组合水槽冲刷试验条件下细沟水流水动力学特征。结果表明：细沟流平均流速与径流流量呈幂函数关系,坡度对其影响较小,其原因同水流强度与床面形态的相互制约有关;黏性底层厚度与坡度、流量均呈现负相关关系;阻力系数与雷诺数无关,说明水流强度增加的同时,床面形态发育愈显著,即水流耗散能量增加愈显著,其值在0.16～1.45之间变化。研究结果对细沟水流水动力学的探究具有一定的理论价值,进而对黄土坡面水土流失治理及生态修复均具有一定的指导意义。[ Background] In the early last century, the problem of soil erosion has been quite serious, thus it is urgent to carry out scientific and effective soil and water conservation work for preventing soil erosion. China is a country with one of the most serious soil erosion, the Loess Plateau is the most serious soil erosion area in the world, and it is also the main source of the Yellow River sediment area; the Loess Plateau region of soil erosion cause not only the deterioration of ecological environment, but also a serious threat to the lower reaches of the Yellow River ecological security. [ Methods] In order to explore the hydrodynamics characteristics of rill flow, the dynamics characteristics of rill flow from the perspective of hydraulics and rivers movement mechanics were studied under the combined scouring test condition of 6 slopes （2°, 4°, 6°, 8°, 10°, and 12°） and 5 discharges （8, 16, 24, 32, and 40 L/min）. [ Results] Results indicated that the average velocity of rill flow was in power function relationship with discharge.However, the there was no correlation between the velocity and slope, which was because the development of drop pits was more mature with the increase of the slope, resulting in the growth of rill flow path. The thickness of the viscous sub-layer was in negative correlation with slope and discharge, and presented an essential effect on rill flow resistance. Resistance coefficient varied from 0. 16 to 1.45 and increased with the increase of the slope and showed no correlation with Reynolds number, meaning that the flow regime belonged to the turbulent rough area, this was because the morphology of bed surface developed significantly, i. e. , the dissipation capacity of the flow increased significantly, with the increase of the intensity of rill flow. [ Conclusions ] The experimental results showed that the bed morphology of loess slope had great influence on the velocity of rill flow. By reasonably changing the bed morphology of loess slope, the flow velocity can be decre

关 键 词：细沟流 细沟流速 阻力系数 细沟侵蚀 黄土高原 

分 类 号：S279.2[农业科学—农业水土工程]