Experimental investigation on the characteristics of hydraulic jump in expanding channels with a water jet injection system

Document Type : Research Paper


1 Department of Hydraulic Structures, College of Water and Environmental Engineering, Shahid Chamran University of Ahvaz,Iran.

2 Department of Civil, Environmental and Architectural Engineering, University of L'Aquila, Via G. Gronchi, 18, 67100 L'Aquila, Italy


The high flow velocity downstream of weirs and gates can cause the destruction of erosive beds in rivers or even non-erosive channels. To reduce the flow's kinetic energy, structures are needed to consume this energy. Expansion basins are often used downstream of structures such as weirs, gates, and chutes to increase energy dissipation in hydraulic jumps. Various methods are used to stabilize asymmetric hydraulic jumps in abrupt expanding channels. In this study, the interaction of multiple submerged water jet injection systems with S-type hydraulic jump for stabilizing and stabilizing the hydraulic jump was investigated. The different configurations of the jet system were tested with Froude numbers 7.4, 8.7, and 9.5, and finally, three optimal configurations were selected as configurations 1, 2, and 3. In order to investigate the performance of the jet injection system under other hydraulic boundary conditions, flow velocities downstream of the jet system were measured for three optimal configurations with different depths of the tailwater. Comparison of the results of using a water jet injection system with S-type hydraulic jump showed that the energy and momentum correction coefficients in all different configurations were significantly reduced. The highest relative energy loss was observed in configuration 3, equal to 68.42%. The results showed a good performance of the jet injection system in stabilizing the asymmetric hydraulic jump S and reducing the length of the stilling basin.


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