Free Flow Over Partially Contracted Triangular-Notch Thin-Plate Weir

The experimental data were obtained using a thin-plate weir (TPW) with a triangular notch at an angle of α=20.23∘, where the weir height P was level with the approach channel bottom. Measurements focused on water levels Zh in the plane of symmetry(at 𝑦=0.000 m) with an approach channel head hU=0.180 m, across different channel widths B(0.064 m, 0.100 m, 0.200 m, 0.300 m, and 0.500 m). Froude (FrU) and Reynolds (ReU) numbers were calculated at various discharge rates Q within the ranges 0.030≤FrU≤0.286 and 7156≤ReU≤67526, confirming subcritical, turbulent flow (FrU < 0.5). Water levels were measured at 10 positions x in the approach channel using a digital point gauge with 0.01 mm resolution, with each reading averaged over 180 seconds (allowable fluctuation ±0.1 mm). Discharges were recorded with an electromagnetic flow meter (DN50), and measurements were conducted under non-aerated conditions for accurate assessment.The velocity field was measured only for the case B = 0.500 m and hU = 0.180 m. Measured were the horizontal velocity components vx,y in horizontal plane z = 0.150 m, the longitudinal velocity components vx in vertical plane y = 0.000 m (plane of longitudinal symmetry) and the longitudinal velocity components vx in transverse plane x = −0.360 m (cross-section U). Also data for CFD simulations are included.

本实验数据采用薄板堰（TPW）进行采集，其中三角缺口处角度为α=20.23∘，堰高P与进水渠底部保持水平。测量主要集中在对称面（y=0.000 m）中的水位Zh，进水渠水位头hU=0.180 m，跨不同渠道宽度B（0.064 m, 0.100 m, 0.200 m, 0.300 m, 以及0.500 m）。在0.030≤FrU≤0.286和7156≤ReU≤67526的范围内，通过多种泄流速率Q计算了弗劳德数（FrU）和雷诺数（ReU），确认了亚临界、湍流状态（FrU < 0.5）。使用具有0.01 mm分辨率的数字点测距仪在进水渠中的10个位置x测量水位，每个读数在180秒内平均（允许波动±0.1 mm）。使用电磁流量计（DN50）记录泄流量，并在非曝气条件下进行测量以确保评估的准确性。仅在B = 0.500 m和hU = 0.180 m的情况下测量了流速场。测量了水平面z = 0.150 m处的水平速度分量vx,y，纵向对称面y = 0.000 m（纵向对称面）中的纵向速度分量vx，以及横截面U中的横向速度分量vx。此外，还包括了CFD模拟所需的数据。