不同长度小麦秸秆覆盖下黄土耕地坡面流水动力学特性

发布时间：2018-01-31 06:27

本文关键词： 流型水动力学秸秆坡面流定床试验黄土耕地　出处：《农业工程学报》2017年04期 　论文类型：期刊论文

【摘要】：为了系统研究秸秆长度对坡面流水动力学特性的影响,利用室内人工模拟冲刷定床阻力试验,在4个坡度、5个流量条件下分别对3~5、8~10和13~15 cm长度秸秆覆盖坡面流水动力学参数变化特征进行分析,阐明不同长度秸秆覆盖坡面水流阻力与雷诺数的关系。结果表明,秸秆长度对坡面流水动力学参数影响显著。不同长度秸秆覆盖条件下,坡面流雷诺数变化范围为166~558,当流量≤7.5 L/min时,坡面流态为层缓流;流量为9.0 L/min时,坡面流态为过渡缓流。秸秆覆盖条件下,坡面流具有较小的流速和较大的水深、Darcy-Weisbach阻力系数及曼宁糙率系数。随着秸秆长度增加,坡面流流速随之增加,而水深、Darcy-Weisbach阻力系数及曼宁糙率系数随之降低。随着秸秆长度和水力坡度增加,流态指数值总体呈现降低趋势。当秸秆长度由3~5 cm增加至13~15 cm时,流态指数平均由0.716降至0.501。研究可为秸秆覆盖条件下水土流失阻控机理研究提供科学依据。
[Abstract]:In order to systematically study the effect of straw length on the dynamic characteristics of income on the slope surface, the resistance test of flushing fixed bed was carried out in laboratory under 4 slopes and 5 flow rates respectively. The variation characteristics of income dynamic parameters on the slope surface with straw cover of 810 cm and 1315 cm were analyzed, and the relationship between the flow resistance and Reynolds number on the slope surface with different length straw mulching was clarified. The results showed that the relationship between the flow resistance and Reynolds number of the slope was studied. The effect of straw length on income kinetic parameters was significant. Under the condition of different length straw mulching, the Reynolds number of slope flow varied from 166 to 558, when the flow rate was less than 7.5 L / min. The flow state of the slope is a layer slow flow; When the flow rate is 9.0 L / min, the slope flow state is transitional slow flow. Under straw mulching condition, the slope flow has smaller flow velocity and larger water depth. Darcy-Weisbach resistance coefficient and Manning roughness coefficient. With the increase of straw length, the flow velocity increased and the water depth increased. Darcy-Weisbach resistance coefficient and Manning roughness coefficient decreased with the increase of straw length and hydraulic slope. When the length of straw was increased from 3 ~ 5 cm to 13 ~ (15) cm, the flow state index showed a decreasing trend. The average flow index was reduced from 0.716 to 0.501. The study can provide scientific basis for the study of soil erosion control mechanism under straw mulching.
【作者单位】：西北农林科技大学水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室;西北农林科技大学资源环境学院;
【基金】：国家自然科学基金(41401309、41330858) 西北农林科技大学博士科研启动基金(2452015345)
【分类号】：S157
【正文快照】： 李朝栋,李占斌,马建业,马波.不同长度小麦秸秆覆盖下黄土耕地坡面流水动力学特性[J].农业工程学报,2017,33(4):153-160.doi:10.11975/j.issn.1002-6819.2017.04.022 http://www.tcsae.org Li Chaodong,Li Zhanbin,Ma Jianye,Ma Bo.Hydraulic characteristic of overland flow

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