A numerical study of viscous granular flow in artificial step-pool systems: flow characteristics and structure optimization

Inspired by the geomorphologic phenomenon of step-pool bed configuration, analogous dissipation structures are set in drainage channels to mitigate granular flow hazards. The sensible design of artificial step-pool systems remains an important and open issue. The discrete element method was utilized in this study to investigate the flow characteristics of viscous granular flow in an artificial step-pool system, and an optimization was proposed. First, a numerical model of the granular flow-structure interaction was given and validated. The influence of design parameters on the velocity reduction ratio P and peak impact force F-max was then investigated. Finally, a new step-pool system was presented and evaluated. The results reveal that: (1) P decreases linearly as the slope i increases. The relative layout spacing omega enhances P, but reduces the efficiency of velocity control per unit length structure; (2) the increase in omega stabilizes the distribution of F-max on 2# to 5# baffles. There exists a peak effect'' of the average peak impact force F-a with the variation of the impact angle beta and the relative baffle height psi (when beta = 75 degrees or psi = 0.27, the F-a reaches a maximum); (3) the optimized structure can control the phenomenon of granular jump while having good guiding performance and more stable impact characteristics. The energy dissipation rate E of optimized structure reaches 91%, an increase of nearly 24% over the original structure.

Automated summary

Inspired by natural step-pool bed configuration, this study investigated the flow characteristics of viscous granular flow in an artificial step-pool system and proposed an optimization method. The results showed that the slope and layout spacing influenced velocity reduction ratio and peak impact force. The optimized structure exhibited improved energy dissipation and stable impact characteristics.