因為台灣地區因氣候關係常有颱風侵襲，颱風來臨時帶來的充沛雨量集中到河川，自然沖刷出主河道和高灘地，當洪水退去時，裸露的高灘地即可以廣泛地被利用，有許多的人為開墾、種植，但是這些植生有增加動植物棲地的益處，另一方面也會產生阻礙水流的害處，所以本篇對於不同佈置方式的柔性植生做流場的研究。
本文在實驗室以15×0.6×0.6m之循環渠道試驗水流通過不同排列的柔性植生群，研究其平均流速與其紊流特性。於渠道入口下游9m處佈置長2m的人工水草群，植生以水族用10cm高的柔性人工水草代表之。實驗中以渠道中央無種植的情況（A組）、和渠道單邊無種植（B組）作為本實驗的不同排列，植生群密度定為66株/m2。
植生群上方及植生群間以 之音波vectrino流速儀量測，所有試驗之流量為0.0357cms。由流速儀所測量到的倒伏植生群上方流速以及無植生部分的流速為基礎，研究其流場情況，並利用積分的方式來計算植生群上方和主河道的流量比例。由實驗數據計算後可以發現，當平滑渠道上種植柔性植生時，在相同種植密度、不同佈置的情況下，使得渠道中大約50%的流量會集中到主河道中，40%的流量會在植生群上方而植生間的流量大約在10%以內。另一方面在植生群和主河道交接的位置，有迴流區的發生，這也顯示了此區域的流量和動量交換現象；另外實驗中也發現，流場中的紊流動能的最大值會發生在倒伏植生最大高度(z/hs=1)時的水深位置。

In Taiwan area often have typhoon attracting during summer times. Typhoon brings abundant rainfall and the rainfall concentrates to the river, naturally washes out the main channel and the river high alluvion. When flood retreat, the exposed high alluvion can be widely used. Agriculture, plant and wetland, these places can increase zoology. On the other hand ,they baffle current of water flow. So this research focuses on different arrangement of flexible vegetation.
An experiment set up to analyze the gradually varied flow through flexible vegetation. In this experiment including two parts, one is no plants at the central of the channel (group A) , and another is no plants at the side of the channel (group B), the density of plant group is 66 stem/ m2. All discharge in the test is 0.0357cms.Using side-looking ADV to measure the part above plants and main channel, and down-looking ADV to measure the part between two plants. Based on these measurement，we can analyze the flow characteristic and realize the discharge distribution at the experiments. After calculating the data, when flexible plant grow on the smooth channel, at the same plant density, about 50% of the discharge in the channel will be concentrated to the main channel, 40% of the discharge upon the plant group and the discharge above the plant group is less than 10%. In these two groups of experiments, the distribution of the discharge are almost the same , the error will prove in the article. On the other hand, there have circulation occurred at the transition zone between plants and main channel, this has shown momentum exchange in this area.

1. 河川區域種植規定修正研究，經濟部水利署，中華民國九十三年六月。
2. 張乃薇，植生渠床定量緩變速流研究，國立成功大學水利及海洋工程研究所碩士論文，中華民國九十五年五月。
3. 張書唐，通過透水結構物急變明渠流場之試驗研究，國立成功大學水利及海洋工程研究所碩士論文，中華民國九十六年七月。
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