正双工新型透水框架消能护滩机理研究

Study on the energy dissipation and beach protection mechanism of a new straight double “H” permeable frame

  • 摘要: 针对传统消能护滩结构存在整体钩连性不足问题,开展了正双工透水框架抛投几何特征、水力消能特性、防冲促淤效果试验研究工作。研究表明:单位面积上,正双工透水框架的抛投高度、孔隙率与抛投层数存在一定关系,每一层抛投高度与孔隙率随着抛投层数的增加而减小并逐渐趋于稳定;正双工透水框架具有阻水消能的作用,抛投后抛投区内时均纵向流速与紊动强度垂线分布均发生调整,并建立了抛投区中心时均纵向流速垂线分布公式;抛投层数越大,框架底部流速减小越大,上层流速增加越大,框架内紊动流速减小幅度越大,而框架表面附近紊动强度增强;当透水框架的抛投长度达到一定距离后,其消能效果趋于稳定;该框架能够对床面进行有效守护,抛投区内泥沙落淤效果显著,且两层正双工字框架的守护效果比一层更好。研究结果有助于推动水利水运工程消能护滩结构研究发展。

     

    Abstract: In view of the insufficient overall interlocking ability of traditional energy dissipation and beach protection structures, this paper conducts experimental research on the casting geometric characteristics, hydraulic energy dissipation properties, and anti-erosion and silt-promoting effects of a straight double “H” permeable frame. The research shows that, per unit area, the casting height and porosity of the straight double “H” permeable frame have a certain relationship with the number of casting layers. The casting height and porosity of each layer decrease as the number of casting layers increases and gradually stabilize. The straight double “H” permeable frame plays a role in water resistance and energy dissipation. After casting, the vertical distribution of the time-averaged longitudinal velocity and turbulence intensity in the casting zone undergoes adjustments, and a vertical distribution formula for the time-averaged longitudinal velocity at the center of the casting zone is established. The greater the number of layers, the more significant the reduction in velocity at the bottom of the frame, the greater the increase in velocity at the top, the greater the decrease in turbulent velocity within the frame, and the more pronounced the increase in turbulence intensity near the frame’s surface. When the casting length of the permeable frame reaches a certain distance, its energy dissipation effect tends to stabilize. The frame effectively protects the bed surface, and sediment deposition in the casting zone is significant. Moreover, the protective effect of a two-layer straight double “H” permeable frame is superior to that of a single-layer one. The research results contribute to advancing the study and development of energy dissipation and beach protection structures in hydraulic and waterway engineering.

     

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