Experimental Study on Hydraulic Model of Reservoir Spillway Under the Front Tail Still

YAO Gang

doi:10.3969/j.issn.1004-7328.2025.04.018

Abstract：To study the influence of shape design on the hydraulic characteristics of spillway discharge under the condition of adding a front tail sill in the spillway of the Daxingzhuang Reservoir Phase Ⅱ Project,a hydraulic model test was designed and conducted.The shape scheme was optimized based on the test results.The test results indicated that the dominant influence of discharge on the horizontal variation trend of flow velocity was higher than that of the shape parameters of the front tail sill.However,controlling the shape parameters of the tail sill helped to suppress the generation of unstable fluid in the discharge section and weaken the hydrodynamic potential energy.The size of the shape parameters of the front tail sill affected the pressure change trend on the spillway section.When the side length of the tail sill was between 5 and 9.5 mm,the tail sill shape cannot effectively cover the stepped submerged surface,leading to a secondary decrease in pressure.As the side length of the tail sill increased,the pressure level did not decrease continuously but increased after reaching 11 mm.With an increase in the shape parameters of the tail sill,the turbulent kinetic energy in the energy dissipation pool decreased while the energy dissipation rate increased.However,when the side length was between 11 and 15 mm,the energy dissipation rate stabilized at 58％.Based on the model test results,it was concluded that a side length of 11 mm for the front tail sill was the optimal solution.The research findings can provide references for the design optimization of the front tail sill of spillways and the analysis of model test monitoring data.