The efficiency of flow energy reduction past emergent vegetation has been typically studied assuming a right angle of the vegetated corridor to the flow direction. However, in many real‐world cases the riparian zones of natural, restored, or engineered rivers and waterways, are found at an oblique angle to the flood flow direction. In the current study, the effect of vegetation angle with respect to the flow direction is investigated experimentally in an open channel rectangular flume. The experiments are conducted under a range of subcritical steady flow conditions, with varying Froude number (Fr_o). The vegetation cover is placed at various angles to the flow direction (90°, 45°, and 30°), for a sparse and intermediate vegetation density, defined from the ratio of spacing of each vegetation element in the cross stream direction (B), and the diameter of vegetation element (d) (B/d = 2.13 and 1.09, respectively). Detailed water surface profiles are obtained for all those cases, demonstrating a considerable backwater rise, increasing with increasing vegetation density, Froude number, and flow approach angle. The energy reduction decreased by increasing the Froude number for the perpendicular (90°) and increased for oblique vegetation (45° and 30°). For the perpendicular vegetation, the average energy reduction rate for sparse (90VS) and intermediate (90VI) vegetation densities are 25.44% and 31.44%, respectively. The range of average energy reduction for sparse vegetation at 45° (45VS) and at 30° (30VS) are 18.3–19.8% and 18.7–19.7%, respectively. Similarly, range of average energy reduction for intermediate vegetation at 45° (45VI) and at 30° (30VI) are 21.4–22% and 18.8–22%, respectively.

中文翻译：

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不同角度植被减洪的实验研究

典型地，假设植被走廊与流向成直角，则研究了越过新兴植被减少流能的效率。但是，在许多实际情况下，发现的自然河，恢复河道或工程河道和河道的河岸带与洪水流动方向呈倾斜角。在当前的研究中，实验研究了开放通道矩形水槽中植被角度对流动方向的影响。实验是在一定范围的亚临界稳流条件下进行的，其中弗洛德数（Fr _o）。植被覆盖物以相对于流动方向（90°，45°和30°）的各种角度放置，以实现稀疏和中等植被密度，该密度由每个植被元素在横流方向（B）上的间距比率确定，和植被元素的直径（d）（B / d分别为2.13和1.09）。对于所有这些情况，都获得了详细的水面轮廓，这表明大量回水，并随着植被密度，弗洛德数和进水角的增加而增加。能量减少通过增加垂直线（90°）的Froude数而减少，而对于倾斜植被（45°和30°）则增加。对于垂直植被，稀疏（90VS）和中间（90VI）植被密度的平均能量减少率分别为25.44％和31.44％。稀疏植被在45°（45VS）和30°（30VS）时的平均能量降低范围分别为18.3-19.8％和18.7-19.7％。同样，中间植被在45°（45VI）和30°（30VI）时的平均能量减少范围分别为21.4–22％和18.8–22％。