Numerical simulation of spatial evolution of coherent motions in submerged rigid vegetation patch flow

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Wanyun Xue, Shiqiang Wu, Xiufeng Wu, Jie Zhou, Jiangyu Dai, Qiuwen Chen

Monday 29 june 2015

16:30 - 16:45h at Europe 1 & 2 (level 0)

Themes: (T) Hydro-environment, (ST) Ecohydraulics and ecohydrology

Parallel session: 3G. Environment - Ecohydraulic

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A number of experimental studies and Large-eddy simulation studies on flow in a rectangular open channel blocked with an artificial submerged rigid vegetation patch have focused on the effects of the coherent structures on momentum transfer across the vegetation edge. The computed results compared well with experimental measurements. A phenomenological model for spatial evolution of coherent motions in submerged vegetation flow was developed on the basis of the numerical results, inducing a subdivision of the whole vegetated flow region. The whole flow region is divided into four zones: the initial flow zone, the diverging flow zone, the developing zone, and the fully developed zone. Shear-layer thickness increased rapidly within the first three zones and stabilized within the fully developed zone because of the limitation of the free surface. Computational results provided insight into the spatial evolution of coherent motions including sweep and ejection motions and the monami phenomena.