This study achieved three goals to clarify the impact of a vegetation patch on flow adjustment and velocity. First, a valid equation for the interior adjustment distance (L_d) inside a model patch was developed for a wide range of velocities and flow depths. Second, the minimum distance inside a patch beyond which the resuspension of fine sediment is suppressed (L_min) was found to be related to the position at which the local velocity decreases to the threshold for generating stem-scale turbulence. L_min primarily depends on the flow blockage (C_dab) and the stem diameter (d): a shorter L_min is a result of a larger C_dab and a smaller d. An equation was formulated for estimating L_min. Third, for the fully developed flow region inside a patch (L > x > L_d), an equation was developed to estimate the increase in the mean velocity in the bare channel relative to the overall mean channel velocity. For C_dab < 2, this fraction is controlled by both the patch density (ad) and the patch blockage (b/B) whereas, for C_dab > 2, this fraction is controlled by only b/B. A suggestion for choosing the patch size in future flow and sediment research projects is presented.

中文翻译：

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新兴模式植被斑块对流量调节和速度的影响

本研究实现了三个目标，以阐明植被斑块对流量调节和速度的影响。首先，针对大范围的速度和流动深度，开发了模型补丁内的内部调整距离 ( L _d )的有效方程。其次，发现细沉积物再悬浮被抑制的斑块内的最小距离（L _min）与局部速度降低到产生茎尺度湍流的阈值的位置有关。L _min主要取决于流量阻塞 ( C _d ab ) 和阀杆直径 ( d )：较短的L _min是较大的C _d ab和较小的d的结果。制定了一个方程来估计L _min。第三，对于斑块内充分发展的流动区域 ( L  >  x  >  L _d )，开发了一个方程来估计裸通道中的平均速度相对于整体平均通道速度的增加。对于C _d ab  < 2，该分数由斑块密度 ( ad ) 和斑块阻塞 ( b / B ) 控制，而对于C _d ab > 2，这个分数仅由b / B控制。提出了在未来流动和沉积物研究项目中选择斑块大小的建议。