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《Journal of Hydrology》刊登“淹没植被不同布置方式对水流特性的影响”
发布时间: 2014-07-07   来源:

《Journal of Hydrology》刊登“淹没植被不同布置方式对水流特性的影响”

作者:Su-Chin Chen , Yi-Ming Kuo ,,Yu-Hsiu Li

刊物:《Journal of Hydrology》,2011年2月,398卷,124–134页

关键词:淹没植被,雷诺应力,紊流,速度分布

摘要:利用室内试验分别研究了淹没植被在3种布置方式下对水流结构的影响。在每种布置方式下,均采用3维多普勒流速仪测量不同位置的时均流速和紊动行为。根据试验结果进行水动力分区,纵向流速的垂直分布可分成3层:上部非植被层,中部植被层,植被根部层。这3层分别对应不同的对数公式,用以描述纵向流速的垂直分布。植被内部的最大速度出现在植物丛的根部(0.10-0.15的植被高度( \* MERGEFORMAT )),因为这个位置阻水面积最小。纵向和横向的紊动强度在植物丛底部和顶部附近位置(0.9-1.2 \* MERGEFORMAT )达到峰值。雷诺应力的最大值出现在0.9-1.2 \* MERGEFORMAT 的位置,此最大值的位置会随着植物丛迎水面积的增加而迁移。高位置的迎水面积也增加植被层上的纵向流速,这也导致植被层顶部的雷诺应力增加。在垂向紊动尺度方面,静止植被层之上的涡比波动植被层之上的涡转动快。因此,试验结果表明:植被丛底部和顶部的流场由于通过的流量改变而发生大的变化。这些分析结果在设计生态栖息地和防止岸坡侵蚀方面是非常有用的。

Flow characteristics within different configurations of submerged flexible vegetation

Authors: Su-Chin Chen , Yi-Ming Kuo ,,Yu-Hsiu Li

Journal: 《Journal of Hydrology》,Volume 398, Issues 1–2, 15 February 2011, Pages 124–134

Key words: Submerged flexible vegetation,Reynolds stress,Turbulence,Velocity profile,Logarithmic law,Open-channel flow

Abstract: The effects of three configurations (aligned, staggered, and columnar) of submerged flexible vegetation on flow structure are investigated experimentally in the laboratory. Time-averaged flow velocity and turbulence behavior are evaluated at different positions in each configuration by using a 3D acoustic Doppler velocimeter (ADV). According to the hydrodynamic regimes in experimental results, the vertical distribution of streamwise velocity can be separated into three layers—the upper non-vegetated layer, middle vegetation layer, and lower sheath layer. This three-layer model, which is associated with different logarithmic equations, can be applied to describe the vertical distribution of streamwise velocity. The local maximum velocity within vegetation occurs at the sheath section of a plant clump (0.10–0.15 vegetation height (Hv)) where the frontal width is minimal. Turbulent intensities in the streamwise (urms) and spanwise (vrms) directions peak at the sheath section and at the approximate top of the canopy (0.9–1.2Hv). The maximum Reynolds stresses exist at roughly 0.9–1.2Hv, which may be migrated vertically as the frontal width of a plant clump is increased. This high frontal width also increases streamwise velocity above vegetation, leading to increase variations in Reynolds stresses around the canopy top. On the vertical turbulent velocity scale (wrms), the vortices above a still canopy rotate faster than those above a waving canopy. Therefore, the experimental results demonstrate that the flow field can vary significantly at the sheath section and at the top of a plant clump due to altered flow pass. These analytical findings will likely prove useful when designing ecological habitats and preventing riverbed erosion.

翻译:杨泽凡;审核:刘淼

原文链接:http://www.sciencedirect.com/science/article/pii/S0022169410007833

 
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