LES study of turbulent flows with submerged vegetation
LES study of turbulent flows with submerged vegetation
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DOI：
10.3826/jhr.2008.3129
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发表时间：
2008-05
影响因子：
2.3
通讯作者：
J. Cui;V. Neary
中科院分区：
文献类型：
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作者：
J. Cui;V. Neary
使用大涡模拟 (LES) 研究水下植被的完全发展的湍流，重点是了解相干结构对水生植物界面动量传递的作用。 LES 模型结果与文献中报告的实验室测量结果相当好。与雷诺平均纳维-斯托克斯模型一样，LES 模型有效地模拟了水下植被对平均流场的影响，但它们也考虑了植被层引起的雷诺应力的各向异性，并解析了瞬时流场中观察到的相干结构。与畅通无阻（无植被）通道中完全发育的流动进行比较，以显示植被如何显着改变植被层内和上方的平均流量、雷诺剪应力、湍流强度、湍流事件频率和能量预算。 LES 提供了直接的视觉证据，表明由于众所周知的开尔文-亥姆霍兹不稳定性，在植被顶部的水生植物界面处形成了相干结构，即展向涡流（卷）和流向涡流（肋）
Fully developed turbulent flows with a submerged vegetation are investigated using Large Eddy Simulation (LES), with a focus on understanding the role of the coherent structures on the momentum transfer across the water-plant interface. The LES model results compare reasonably well with laboratory measurements reported in the literature. As with Reynolds-Averaged Navier–Stokes models, LES models effectively simulate the effects of submerged vegetation on the mean flow field, but they also account for the anisotropy of the Reynolds stresses due to the vegetation layer, and resolve coherent structures observed in the instantaneous flow field. Comparisons with fully developed flows in unobstructed (non-vegetated) channels are made to show how the vegetation significantly changes the mean flow, Reynolds shear stress, turbulence intensities, turbulence event frequencies and the energy budget within and above the vegetation layer. LES provides direct visual evidence that coherent structures, namely spanwise vortices (rolls) and streamwise vortices (ribs), develop at the water-plant interface at the top of the vegetation due to the well-known Kelvin–Helmholtz instability