This study investigates the effectiveness of flow splitters in reducing scour downstream of trapezoidal Piano Key Weirs through a comprehensive experimental study. Three distinct geometries of flow splitters—square, rectangular, and circular—are examined under various hydraulic conditions to assess their impact on local scouring. The experiments were conducted in a dedicated channel measuring 10 m in length, 0.75 m in width, and 0.80 m in height. The results indicate that flow splitters facilitate flow separation by linking trapped air beneath the flow to the free surface, thereby mitigating nappe oscillation. Additionally, the geometric variations of flow splitters did not significantly influence the upstream water head, with rectangular-shaped flow splitters proving more effective than square and circular splitters. On average, the maximum scour depth for the weir with rectangular, square, and circular splitters is reduced by approximately 13, 11, and 10%, respectively, compared to the weir without splitters. Furthermore, the volume of scour holes in tests with rectangular, square, and circular splitters showed reductions of 18.53, 17.77, and 14.92%, respectively, compared to tests without splitters. As discharge decreases, the effectiveness of these flow splitters in reducing scour depth becomes more pronounced. Due to the existence of splitters, the location of maximum scour depth approaches the weir. New equations were developed for predicting scour hole parameters with and without flow splitters, incorporating various splitter geometries. These equations were formulated using non-linear regression, achieving high accuracy with a correction factor, yielding R² values between 0.78 and 0.94, and RMSE values ranging from 0.09 to 0.54. Overall, the findings underscore the significance of flow splitter geometry in mitigating scour effects, providing valuable insights for future engineering applications.

本研究通过一项全面的实验研究，调查了分流器在减少梯形钢琴键堰下游冲刷方面的有效性。在各种水力条件下检查分流器的三种不同几何形状（方形、矩形和圆形），以评估它们对局部冲刷的影响。实验在长 10 m、宽 0.75 m 和 高 0.80 m 的专用通道中进行。结果表明，分流器通过将流动下方的滞留空气与自由表面连接起来，从而促进流动分离，从而减轻 nappe 振荡。此外，分流器的几何变化并没有显着影响上游水头，矩形分流器被证明比方形和圆形分流器更有效。平均而言，与没有分流器的堰相比，带有矩形、方形和圆形分流器的堰的最大冲刷深度分别减少了约 13%、11% 和 10%。此外，与没有分流器的测试相比，使用矩形、方形和圆形分流器的测试中，冲刷孔的体积分别减少了 18.53%、17.77% 和 14.92%。随着排放量的减少，这些分流器在减少冲刷深度方面的有效性变得更加明显。由于存在分流器，最大冲刷深度的位置接近堰。开发了新的方程式，用于预测有和没有分流器的冲刷孔参数，并结合了各种分流器几何形状。这些方程是使用非线性回归公式化的，通过校正因子实现高精度，产生介于 0.78 和 0.94 之间的 R² 值和 0.09 到 0.54 之间的 RMSE 值。 总体而言，这些发现强调了分流器几何形状在减轻冲刷效应方面的重要性，为未来的工程应用提供了有价值的见解。