The interaction between confluence and vegetation is important for understanding the rules of flood control and ecological restoration. To this end, artificial flexible plastic grass was used in a 90° confluent open channel to simulate the ambient conditions of the natural state, and three-dimensional velocities were measured by an acoustic Doppler velocimeter. The velocities of different spatial distribution in different conditions were analysed. The results showed that the existence of vegetation will change the velocity's horizontal distribution and the velocity decreases greatly because of the vegetation. The vegetation reduces the deflection angle of the 90° confluence flow intersection. Under the influence of the vegetation, the flow direction can be restored to the main flow direction more quickly after confluence. Vegetation is the main factor causing the flow velocity reduction in the upstream, whereas in the vicinity of the confluence the influence of vegetation on the velocity will change with the intensity of the turbulence in the region. The influence range of the vegetation on the vertical velocity was found to be double the average height of the vegetation. The vertical velocities changes greatly near the average height of the vegetation.

中文翻译：

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有柔性植被和无柔性植被的合流通道流速特性

汇流与植被之间的相互作用对于理解防洪和生态恢复规律具有重要意义。为此，在90°汇合的明渠中使用人造柔性塑料草模拟自然状态的环境条件，并通过声学多普勒测速仪测量三维速度。分析了不同条件下不同空间分布的速度。结果表明，植被的存在会改变速度的水平分布，速度会因植被而大大降低。植被减少了 90° 汇流交叉口的偏转角。在植被的影响下，汇流后的流向可以更快地恢复到主流向。植被是造成上游流速降低的主要因素，而在汇合处附近植被对流速的影响会随着该地区湍流的强度而变化。发现植被对垂直速度的影响范围是植被平均高度的两倍。垂直速度在植被平均高度附近变化很大。