The hydraulic behavior of the arched sharp-crested weirs is investigated and compared with rectangular weirs in this research. For this purpose, a laboratory study was made on a physical model, including weirs with four different arc lengths each with five different heights. Experiments were carried out in free flow condition and in both aerated and non-aerated cases of weirs. Laboratory data were discharge rate and water head amount on weir. The water head on weir has been read over the course of various discharge flows over a range of about 3–140 l/s. Test results proved that the arched weir discharge coefficient, while seriously dependent on the $$\frac{H}{P}$$ H P ratio, is also a function of the weir arc length. The variations of this coefficient with respect to $$\frac{H}{P}$$ H P ratio are nonlinear and different from rectangular weir one. It will be reduced and attain an almost constant amount by increasing the ratio. Experimental results show that the circle discharge coefficient amount is bigger than rectangular one in $$\frac{H}{P}$$ H P values less than 0.2 and it is smaller than one in $$\frac{H}{P}$$ H P ratio more than 1.2. Moreover, arched weir discharge value is always more than the rectangular weir in the same status. In the range of present experiments, increments of the arched weir discharge relative to the rectangular vary from 10 up to 80%. It depends on the height and length of the weir crest.

中文翻译：

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拱形尖顶堰流的试验研究及与矩形堰的比较

本研究对拱形尖顶堰的水力行为进行了研究，并与矩形堰进行了比较。为此，对物理模型进行了实验室研究，该模型包括具有四种不同弧长的堰，每一种具有五种不同的高度。实验是在自由流动条件下以及在堰的充气和非充气情况下进行的。实验室数据为堰上的排放量和水头量。在大约 3–140 l/s 范围内的各种排放流量过程中读取了堰上的水头。试验结果证明，拱形堰流量系数虽然严重依赖于$$\frac{H}{P}$$ HP 比率，但也是堰弧长度的函数。该系数相对于 $$\frac{H}{P}$$ HP 比率的变化是非线性的，与矩形堰不同。通过增加比率，它将减少并达到几乎恒定的数量。实验结果表明，$$\frac{H}{P}$$ HP值小于0.2时，圆形流量系数大于矩形，$$\frac{H}{P}$小于1 $ HP比1.2多。而且，拱形堰的流量值总是大于相同状态下的矩形堰。在目前的实验范围内，拱形堰流量相对于矩形的增量从 10% 到 80% 不等。这取决于堰顶的高度和长度。2 并且在$$\frac{H}{P}$$ HP 比率中小于1 大于1.2。而且，拱形堰的流量值总是大于相同状态下的矩形堰。在目前的实验范围内，拱形堰流量相对于矩形的增量从 10% 到 80% 不等。这取决于堰顶的高度和长度。2 并且在$$\frac{H}{P}$$ HP 比率中小于1 大于1.2。而且，拱形堰的流量值总是大于相同状态下的矩形堰。在目前的实验范围内，拱形堰流量相对于矩形的增量从 10% 到 80% 不等。这取决于堰顶的高度和长度。