Abstract The rounded crested weirs are commonly used for discharge measurements and this overflow structures have advantages such as stable overflow pattern and good accuracy. Hydrofoil weirs with streamlined properties are similar to the ogee weirs and can be used as a spillway profile. The hydraulic features of flow over hydrofoil weirs created by the NACA0018, NACA0021 and NACA0024 hydrofoil geometry placed in an open channel are investigated experimentally under free-flow conditions. The velocity field of hydrofoil weir flows are measured by one-dimensional Laser Doppler Anemometer. Experimental velocity profiles are measured along the middle section of the channel, especially around the weir structure, to determine the boundary layer separation. According to the determination of optimum weir structure the free surface profiles, pressure distributions on weir surfaces, experimental discharge coefficients and head losses over weir structures are determined for different structure and flow conditions. Pressure distributions over the hydrofoil weir are presented. In addition, the relationships between discharge coefficient (Cd) and flow rate (Q), specific total head (H/R), relative weir height (P/H), relative total head (H/P) and dimensionless total energy head upstream of the weir (H/L) are investigated.

中文翻译：

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水翼堰上流动特性的实验分析

摘要 圆顶堰常用于流量测量，这种溢流结构具有溢流形态稳定、精度好等优点。具有流线型特性的水翼堰类似于 ogee 堰，可用作溢洪道剖面。在自由流动条件下，通过实验研究了放置在明渠中的 NACA0018、NACA0021 和 NACA0024 水翼几何形状产生的水翼堰上流动的水力特征。水翼堰流速度场由一维激光多普勒风速仪测量。沿着通道的中间部分测量实验速度剖面，特别是在堰结构周围，以确定边界层分离。根据最佳堰结构确定自由面轮廓，堰表面的压力分布、实验流量系数和堰结构上的水头损失是针对不同的结构和流动条件确定的。展示了水翼堰上的压力分布。此外，流量系数（Cd）与流量（Q）、比总水头（H/R）、相对堰高（P/H）、相对总水头（H/P）和上游无因次总能量水头的关系对堰 (H/L) 进行了研究。