针对消力池消能不充分、流态紊乱等问题,提出一种V形墩新型辅助消能工增加消能率η,并引入水跃位置前移率P作为评价指标用以量化V形墩对水跃位置的调控效果。通过模型试验与数值模拟相结合的方法分析弗劳德数Fr、夹角θ、排间距γ、首排墩位置Γ、墩高比ξ、收缩比β等因素对η和P的影响。结果表明:Fr对η影响最显著,最优方案下η为95.58%;Γ及ξ对P影响最显著,最优方案下P为49.42%。V形墩通过增强紊动与漩涡耗能,跃前断面最大流速下降幅度达39.4%,有效抑制大尺度涡旋发展。V形墩消力池较传统消力池流态更平稳,能量耗散更充分。研究成果可为类似工程消能工设计提供理论依据。

[Objective] This study aims to solve the problem of insufficient energy dissipation and flow disorder in stilling basins with low Froude number. The V-shaped pier is proposed, and the forward displacement rate of hydraulic jump position P is introduced as an evaluation indicator to quantify the effect of hydraulic jump regulation. The main purpose is to systematically examine the effects of Froude number Fr, V-shaped pier angle θ, row spacing γ, first row pier position Γ, pier height ratio ξ, and contraction ratio β on energy dissipation rate η and P, to reveal the corresponding energy dissipation mechanisms and provide optimal design parameters for practical engineering applications. [Methods] Physical model tests and numerical simulation were adopted to analyze flow field structure, turbulent kinetic energy dissipation rate, and turbulent scale. The physical model consists an upstream water tank, a test section, a triangular water weir, and a backwater system. The experimental design based on L₁₈ (3⁷) orthogonal table was used to evaluate the effects of six factors at three levels on η and P. At the same time, a three-dimensional numerical model using the RNG k-ε turbulence model was established to simulate both the optimal V-shaped pier condition and the non-pier condition. [Results] The orthogonal test results showed that Fr had the most significant effect on the energy dissipation rate η, and η increased notably with the increase of Fr (2.77-4.91). Under the optimal scheme, the energy dissipation rate η reached 95.58%. For the forward displacement rate P of the hydraulic jump position, the first row pier position Γ and the pier height ratio ξ demonstrated the greatest effects, and P reached 49.42% under the optimal scheme. The variance analysis verified the significance of each factor and determined the globally optimal parameter combination at Fr=4.91. Numerical simulations indicated that compared with the non-pier condition, the V-shaped pier layout reduced the maximum velocity of the pre-jump section by 39.4%, significantly shortening the flow field homogenization distance. The peak turbulent kinetic energy dissipation rate ε near the first row of piers was 14.52% higher than that in the non-pier case, indicating enhanced energy dissipation through strong shear and vortex action. The turbulence length scale L_T near the pier decreased to about 0.02 m, effectively suppressing the development of large-scale vortices. Downstream of the second row of piers, the L_T was homogenized to about 0.10 m, and the vortex scale at the apron was reduced by 81.25% to 0.03 m, reflecting a multi-stage vortex synergy energy dissipation mechanism. [Conclusion] The V-shaped pier proves to be an efficient auxiliary energy dissipator for stilling basins with low Froude numbers. The optimal parameter combination was determined as θ=90°, γ=0.2L, Γ=0.2L, ξ=0.66, β=0.26, which achieved an η of 95.58% and P of 49.42%. Overall, the V-shaped pier fundamentally optimizes the flow field, significantly improves the flow stability and energy dissipation efficiency, and reduces the downstream scour risk through mechanisms of diversion, impingement, shear, and multi-stage vortex dissipation. Future studies should focus on establishing the optimal parameter combination relationships in a wider range of Froude numbers.