Laboratory experiments examined the longitudinal evolution of near-bed velocity, turbulent kinetic energy (TKE), and net deposition in a model Phragmites australis canopy occupying 1/3 of the channel width. The canopies were constructed from model P. australis with real morphology and a solid volume fraction between 0.003 and 0.018. An exponential model was modified to predict the longitudinal evolution of near-bed velocity inside the canopy, from which the near-bed TKE can be predicted. By combining the predicted TKE and a deposition probability, we proposed a model to predict the distribution of net deposition inside the canopy. The predicted velocity, TKE, and deposition were in good agreement with the measurements. Relative to an upstream reference, the net deposition within the canopy was enhanced when two conditions were met: the in-canopy, near-bed TKE was smaller than the critical value for resuspension, and resuspension took place in the bare channel. Above a critical vegetation density (defined by a critical solid volume fraction ϕ_c), the spatially-averaged deposition inside P. australis surpassed that in the adjacent bare channel. The proposed model provides a way to estimate ϕ_c. Relative to the upstream reference, deposition inside the canopy was always diminished over some fraction of the flow adjustment distance, L_d (distance from canopy leading edge to fully developed flow). When the canopy length was greater than 0.4 L_d, canopy-averaged deposition was enhanced relative to the bare channel. Finally, for the same canopy length, differences in plant morphologies did not have a strong impact on the in-canopy deposition distribution.

中文翻译：

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部分充满芦苇树冠的通道中的速度、湍流和沉积物沉积

实验室实验检查了占据通道宽度 1/3 的模型芦苇冠层中的近床速度、湍动能 (TKE) 和净沉积的纵向演变。檐篷由模型P建造。澳大利亚具有真实形态和 0.003 和 0.018 之间的固体体积分数。修改了指数模型以预测冠层内近床速度的纵向演变，由此可以预测近床TKE。通过结合预测的 TKE 和沉积概率，我们提出了一个模型来预测冠层内的净沉积分布。预测的速度、TKE 和沉积物与测量结果非常吻合。相对于上游参考，当满足两个条件时，冠层内的净沉积物会增加：冠层内近床 TKE 小于再悬浮的临界值，再悬浮发生在裸露的通道中。高于临界植被密度（由临界固体体积分数φ _c定义）)， P内部的空间平均沉积。australis超过了邻近的裸河道。所提出的模型提供了一种估计φ _c的方法。相对于上游参考，冠层内的沉积物总是在流量调节距离L _d（从冠层前缘到充分发展的流量的距离）的一部分内减少。当冠层长度大于 0.4  L _d时，冠层平均沉积相对于裸通道增强。最后，对于相同的冠层长度，植物形态的差异对冠层内沉积分布没有很大影响。