Research progress on weakening mechanisms and key technologies of energy dissipation by hydraulic jumps with low Froude numbers

Abstract

[Objective] As an important hydraulic phenomenon, hydraulic jumps are widely used for energy dissipation in water conservancy projects. Hydraulic jumps with low Froude numbers tend to form wavy structures, and the energy dissipation rate is often unsatisfactory, resulting in severe scouring and damage to the downstream energy dissipation and anti-scouring facilities. [Methods] Therefore, the weakening mechanisms of energy dissipation by hydraulic jumps with low Froude numbers are analyzed and summarized from the perspectives of mechanical mechanisms and external conditions. The understanding of the structure and energy dissipation pathways of hydraulic jumps with low Froude numbers is deepened by considering water body structure, bubble entrainment, and their interactions. Based on the understanding of the weakening mechanisms, key technologies and mechanisms related to stilling basin design, stilling basin structure optimization, auxiliary energy dissipator application, and aeration rectification energy dissipation are reviewed to guide engineering design. Additionally, key technologies are highlighted for addressing derivative problems such as cavitation erosion of auxiliary energy dissipators, sediment deposition in stilling basins, and fish mortality caused by supersaturated dissolved gases in water. [Results] It is found that due to the inherent complexity of hydraulic jump structures and the limitations of modern flow measurement techniques, systematic knowledge gaps remain in the research on the turbulent structures and energy dissipation mechanisms of hydraulic jumps with low Froude numbers. In engineering applications, there is a lack of universal design criteria to guide engineering optimization, and the establishment of an engineering ecological impact assessment system is urgently needed. [Conclusion] In the future, physics-informed neural networks and machine learning technologies can be used to carry out further research in three aspects: in-depth investigation of two-phase flow mechanisms of hydraulic jumps, optimization of energy dissipator design method, and the establishment of multi-objective evaluation systems for engineering schemes.

Keywords

low Froude number / energy dissipation by hydraulic jump / weakening mechanism / key technology / energy dissipation mechanism / energy dissipation rate / hydraulic characteristics / cavitation