水生植被群尾流受淹没度影响，与局部水流特性和营养物质的分布产生积极响应。借助圆形竹签进行交错排布，模拟不同淹没度下的刚性植被群，通过室内水槽实验，研究淹没度对植被群尾部水流纵向分布的作用机理。实验结果表明：淹没度较大时（植被群生长初期），植被群正后方水流变化平缓，流速与紊动能峰值均接近于上游平均值；不同淹没度下的植被群尾部受卡门涡流影响，均能产生含有两个峰值的紊动能，且分别对应流速极小值；淹没度较小时（植被群生长后期），尾部正后方紊动能变化幅度增大，卡门涡流影响作用逐步减小，不利于植被群的纵向扩展。
Abstract
The wake structure of aquatic vegetation patch is influenced by submergence degree，having a positive response to local flow
characteristics and the distribution of nutrients． Through the flume experiment，research is done on the mechanism of the effect of
submergence on the longitudinal flow distribution of wake． The experimental results show that when the degree of submergence is large( early
growth stage) ，the flow is directly behind the vegetation patch change uniformly，the peak value of velocity and turbulent kinetic energy are
close to the average value of the upstream． Affected by Karman vortex，the patch wake of different submergence degree can produce turbulent
kinetic energy containing the two peak values． When the degree of submergence is small ( late growth stage) ，the variation of turbulent kinetic
energy directly behind the patch increases gradually，with the effect of von Karman vortex reduced，is not conducive to the longitudinal
extension of vegetation patch．
关键词
植被群尾流 /
淹没度 /
流速 /
紊动能
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Key words
vegetation wake /
submergence degree /
velocity /
turbulent kinetic energy
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基金
国家自然科学基金资助项目( 51539007) ; 国家重点研发
计划资助项目( 2016YFC0402302)
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参考文献
[1] Yang K, Cao S, Knight D W. Flow patterns in compound channels with vegetated floodplains[J]. Journal of Hydraulic Engineering, 2007, 133(2): 148-159.
[2] Sand-Jensen K, Pedersen M L. Streamlining of plant patches in streams[J]. Freshwater Biology, 2008, 53(4): 714-726.
[3] Tanaka N, Yagisawa J. Flow structures and sedimentation characteristics around clump-type vegetation[J]. Journal of Hydro-environment Research, 2010, 4(1): 15-25.
[4] Vandenbruwaene W, Temmerman S, Bouma T J, et al. Flow interaction with dynamic vegetation patches: implications for biogeomorphic evolution of a tidal landscape[J]. Journal of Geophysical Research: Atmospheres, 2011, 116(F1): 155-170.
[5] Liu C, Luo X, Liu X, et al. Modeling depth-averaged velocity and bed shear stress in compound channels with emergent and submerged vegetation[J]. Advances in Water Resources, 2013, 60: 148-159.
[6] Shan Y, Liu C, Luo M. Simple analytical model for depth-averaged velocity in meandering compound channels[J]. Applied Mathematics and Mechanics (English Edition), 2015, 36(6): 1-12.
[7] Liu C, Wright N, Liu X, et al. An analytical model for lateral depth-averaged velocity distributions along a meander in curved compound channels[J]. Advances in Water Resources, 2014, 74: 26-43.
[8] Liu C, Shan Y, Liu X, et al. The effect of floodplain grass on the flow characteristics of meandering compound channels[J]. Journal of Hydrology, 2016, 542: 1-17.
[9] Liu C, Nepf H. Sediment deposition within and around a finite patch of model vegetation over a range of channel velocity[J]. Water Resources Research, 2016, 52(1): 600-612.
[10] Ortiz A C, Ashton A, Nepf H. Mean and turbulent velocity fields near rigid and flexible plants and the implications for deposition[J]. Journal of Geophysical Research: Earth Surface, 2013, 118(4): 2585-2599.
[11] Chen Z, Ortiz A, Zong L, et al. The wake structure behind a porous obstruction and its implications for deposition near a finite patch of emergent vegetation[J]. Water Resources Research, 2012, 48(9): 2997-3002.
[12] Folkard A M. Hydrodynamics of model posidonia oceanica patches in shallow water[J]. Limnology and Oceanography, 2005, 50(5): 1592-1600.
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