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ics，2017，831：1-40 .
［ 10］ CHEN Z，ORTIZ A，ZONG L，et al . The wake structure behind a porous obstruction and its implications for de⁃
position near a finite patch of emergent vegetation［J］. Water Resources Research，2012，48（9）：1-12 .
［ 11］ ZONG L，NEPF H . Vortex development behind a finite porous obstruction in a channel［J］. Journal of Fluid Me⁃
chanics，2012，691：368-391 .
［ 12］ SCHANDERL W，JENSSEN U，STROBL C，et al . The structure and budget of turbulent kinetic energy in front
of a wall-mounted cylinder［J］. Journal of Fluid Mechanics，2017，827：285-321 .
［ 13］ SAHIN M，OWENS R G . A numerical investigation of wall effects up to high blockage ratios on two-dimensional
flow past a confined circular cylinder［J］. Physics of Fluids，2004，16（5）：1305-1320 .
［ 14］ KUMAR B，MITTAL S . Effect of blockage on critical parameters for flow past a circular cylinder［J］. Internation⁃
al Journal for Numerical Methods in Fluids，2006，50（8）：987-1001 .
［ 15］ NICOLAI C，TADDEI S，MANES C，et al . Wakes of wall-bounded turbulent flows past patches of circular cylin⁃
ders［J］. Journal of Fluid Mechanics，2020，892：A37 .
［ 16］ SUMNER D . Flow above the free end of a surface-mounted finite-height circular cylinder：a review［J］. Journal
of Fluids and Structures，2013，43：41-63 .

Investigation of the mean wake structures
of submerged vegetation patches based on PIV measurement

LIU Mengyang，HUAI Wenxin
（State Key Laboratory of Water Resources and Hydropower Engineering Science，Wuhan University，Wuhan 430072，China）

Abstract：The flow around submerged vegetation patches plays a critical role in material transportation and
vegetation evolution. This study used particle image velocimetry to investigate the effects of array density on
mean wakes of submerged vegetation patches modeled as circular rigid cylinder arrays， based on laboratory
flume experiments. The results showed that the streamwise bleeding flow decreased as the array became
denser，and was also affected by the patches’diameters. When the array density was larger than 0.1，the
group behavior of the array became significant and a symmetric “arch” vortex was formed behind the ar⁃
ray， similar to a submerged solid cylinder， and moved closer to the array with increasing array density.
The length of the steady wake region was approximately linearly correlated with the distance from the arch
vortex to the array. This study is of great significance for further understanding the flow structures around
vegetation patches.
Keywords：vegetation patch；wake；PIV measurement；vegetation density；submerged vegetation

（责任编辑：李福田）

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