Flow resistance of flexible and stiff vegetation:: a flume study with natural plants
Flow resistance of flexible and stiff vegetation:: a flume study with natural plants
复制标题
DOI：
10.1016/s0022-1694(02)00193-2
复制
发表时间：
2002-12-01
影响因子：
6.4
通讯作者：
Järvelä, J
中科院分区：
文献类型：
--
作者：
Järvelä, J
在实验室水槽中研究了天然草、莎草和柳树的水流阻力。其目的是调查，如何类型，密度和位置的植被，流动深度和速度的影响摩擦损失。在非淹没和淹没条件下，在总共350个测试运行的各种组合的植物进行了研究。结果表明，大的变化的摩擦系数，f与流的深度，速度，雷诺数，和植被密度。摩擦系数主要取决于（1）草的相对粗糙度;（2）柳树和莎草/草组合的流速;（3）裸露底层土壤上无叶柳树的水流深度。柳树上的叶子似乎是无叶情况下摩擦系数的两倍甚至三倍，尽管在两种情况下底部都生长着莎草。对于无叶柳树，f似乎随深度几乎线性增加，且与速度无关。相同数量的无叶柳树与草的不同间距对水流阻力的影响不显著。通过试验，进一步了解了在非淹没和淹没条件下，天然刚性和柔性植被的不同组合对水流阻力的影响。(C)2002 Elsevier Science B. V.保留所有权利。
Flow resistance of natural grasses, sedges and willows was studied in a laboratory flume. The objective was to investigate, how type, density and placement of vegetation, flow depth and velocity influence friction losses. The plants were studied in various combinations under nonsubmerged and submerged conditions in a total of 350 test runs. The results show large variations in the friction factor, f with depth of flow, velocity, Reynolds number, and vegetative density. The friction factor was dependent mostly on (1) the relative roughness in the case of grasses; (2) the flow velocity in the case of willows and sedges/grasses combined; and (3) the flow depth in the case of leafless willows on bare bottom soil. Leaves on willows seemed to double or even triple the friction factor compared to the leafless case despite the fact that the bottom was growing sedges in both cases. For the leafless willows, f appeared to increase with depth almost linearly and independently of velocity. Unexpectedly, different spacing of the same number of leafless willows with grasses did not have any significant effect on f Based on the experimental work, a better understanding of flow resistance due to different combinations of natural stiff and flexible vegetation under nonsubmerged and submerged conditions was gained. (C) 2002 Elsevier Science B.V. All rights reserved.