模拟植被地表覆盖率与地表粗糙度对坡面流流速的影响

发布时间：2018-02-12 04:47

本文关键词： 坡面流流速地表覆盖率粗糙度流态指数　出处：《浙江农业学报》2017年03期 　论文类型：期刊论文

【摘要】：采用定床冲刷实验,在3个坡度(5°、10°、15°),9个单宽流量(0.2~0.6 L·m~(-1)·s~(-1)),4个地表覆盖率(0、1.7%、3.5%、6.1%)及4个粗糙度(0.009,0.12,0.18,0.38)影响下,系统研究坡面流流速与地表覆盖率、粗糙度、坡度及流量间的关系。结果表明:在实验条件下,坡面流流速的变化范围为0.25~0.60 m·s~(-1),各工况条件下坡面流流速随着流量增加呈幂指数增加,随着坡度的增加而显著增加,随着粗糙度、地表覆盖率的增加而减小。各影响因子对坡面流直接作用的影响程度大小排序为坡度(0.821)流量(0.358)粗糙度(-0.287)地表覆盖率(-0.123)。所有坡面流能量都是以克服阻力做功为主(m0.5),转化动能为辅。随着粗糙度的增加,坡面流用于克服阻力做功的能量也在增加。当地表覆盖率最大时,能量消耗于阻力做功最多;但在地表覆盖率较小时,能量消耗差异不明显。
[Abstract]:In the fixed bed scour experiment, under the influence of 3 slopes (5 掳/ 10 掳/ 15 掳/ m ~ (-1), 9 / wide / 0. 2 ~ 0. 6 L 路m ~ (-1)) 路scai ~ (-1), 4 / 1 / 3. 5 ~ 3. 5 ~ 6 ~ (1)) and 4 roughness (0. 009 0. 120.18 ~ 0. 38)), the flow velocity and surface coverage, roughness, roughness of slope flow are studied systematically. The results show that, under the experimental conditions, the variation range of flow velocity is 0.25 ~ 0.60 m 路s ~ (-1) m 路s ~ (-1), and the flow velocity increases exponentially with the increase of flow rate, and increases significantly with the increase of slope. With roughness, The degree of influence of each influencing factor on the direct effect of slope flow is in the order of slope gradient (0.821), flow rate (0.358) roughness, and surface coverage: -0.123. All the energy of slope flow is mainly to overcome the resistance, and the energy of all slope flow is mainly work to overcome the resistance of the slope flow, and the order of the influence degree is: the slope degree is 0.821) the flow rate is 0.358) the roughness is 0.287). With the increase of roughness, The energy used by slope flow to overcome the resistance work is also increasing. When the surface coverage is the largest, the energy consumption is the most, but the difference of energy consumption is not obvious when the surface coverage is small.
【作者单位】：北京林业大学水土保持学院;
【基金】：国家林业局林业公益性行业科研专项经费项目(201004018)
【分类号】：S157

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