Abstract Weirs are a type of hydraulic structures that are used in water supply systems and irrigation networks for different purposes. These structures are categorized as different types and must be selected in respect to the hydraulic conditions to satisfy all the objectives of a project. The present study subjects to investigate the hydraulic characteristics of flow over the streamlined weirs, based on model experimentation. The streamlined weirs are a special type of weirs, designed based on the airfoil theory. These weirs have some merits compared to the other types of weirs. They have high discharge coefficient, more stability and less fluctuations of water free surface. According to the objectives of the present study, an experimental investigation was performed, using different experimental models of the streamlined weirs, designed according to the Joukowsky transform function. Experimental results inferred that for a constant flow discharge, the upstream flow heads over the streamlined weirs with different relative eccentricities are almost constant, showing an approximately constant discharge coefficient by the variation of the relative eccentricities. Furthermore, adding a downstream sloped face does not change the flow discharge coefficient. However, increasing the weir height, results in the increase of the flow head and the decrease of the flow discharge coefficient, especially, for the higher heads and the lower relative eccentricities.

中文翻译：

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基于模型试验的流线型堰溢流特性

摘要 堰是一种用于供水系统和灌溉网络的水工结构，具有不同的用途。这些结构分为不同类型，必须根据水力条件进行选择，以满足项目的所有目标。本研究以模型试验为基础，研究流线型堰上水流的水力特性。流线型堰是一种特殊类型的堰，是根据翼型理论设计的。与其他类型的堰相比，这些堰有一些优点。流量系数高，稳定性好，自由水面波动小。根据本研究的目的，使用流线型堰的不同实验模型进行了实验研究，根据 Joukowsky 变换函数设计。实验结果推断，对于恒定流量，不同相对偏心率的流线型堰上上游水头几乎恒定，通过相对偏心率的变化显示出近似恒定的流量系数。此外，增加下游倾斜面不会改变流量系数。然而，增加堰高，导致流头增大，流量系数减小，特别是对于较高的水头和较低的相对偏心。通过相对偏心率的变化显示出近似恒定的流量系数。此外，增加下游倾斜面不会改变流量系数。然而，增加堰高，导致流头增大，流量系数减小，特别是对于较高的水头和较低的相对偏心。通过相对偏心率的变化显示出近似恒定的流量系数。此外，增加下游倾斜面不会改变流量系数。然而，增加堰高，导致流头增大，流量系数减小，特别是对于较高的水头和较低的相对偏心。