Experimental investigation of the sequent depth ratio in hydraulic jumps occurring in a sloped compound rectangular channel with a rough minor bed

ABSTRACT Hydraulic jumps are fundamental phenomena in open channel flows, playing a crucial role in energy dissipation, particularly downstream of structures such as block ramps and rock-filled chutes. This study presents an experimental investigation of hydraulic jump characteristics in a sloped compound rectangular channel with a rough minor bed. The research focuses on the effects of uniform bed roughness and channel slope on the sequent depth ratio. A series of experiments were conducted with four positive slopes and five roughness levels using artificially roughened beds made from uniform plastic pellets. Comparative analyses of hydraulic jumps over smooth and rough minor beds reveal that increased roughness significantly reduces the conjugate depth ratio while enhancing energy dissipation. Empirical relationships were developed, linking the incident Froude number, conjugate depth ratio, relative roughness (ɛ/b), and channel slope. The findings provide valuable insights for optimizing hydraulic structures, particularly in designing energy dissipation basins for dams and irrigation systems, where controlled flow management is essential.