Numerical and analysis effects of rectangular prism rough beds on hydraulic jumps in open channels

Hydraulic jumps are characterized by intense turbulence and substantial energy dissipation in open channel flows or stilling basins. This study utilizes the Flow-3D hydraulic computational model, integrating the renormalization group k-ε turbulence model with the volume of fluid method, to investigate hydraulic jump behavior over rectangular prism rough beds. The findings reveal that these rough beds significantly influence hydraulic jump characteristics, leading to reductions of ∼17% in conjugate depth and 50% in jump length compared to classical hydraulic jumps. In addition, the vortex in hydraulic jumps is also used to clearly explain energy dissipation, which shows that the rough bed configuration significantly influences the hydraulic jump length. The results clarify the relationship between the hydraulic jump characteristics and the rough bed types studied. Moreover, this research provides valuable guidelines for choosing the geometrical features of the rough bed when designing or repairing the stilling basin for irrigation works and highway sewers downstream.