Experimental investigation of water jet injection system on the stability of asymmetric jumps in expanding channels

The high velocity of flow downstream of weirs and gates can cause the destruction of erosive beds in rivers or even non-erosive channels. To reduce the kinetic energy of the flow, structures are needed to consume this energy. These structures include stilling basins. Expansion basins are often used downstream of structures such as weirs, gates, and chutes to increase energy dissipation in hydraulic jumps. The length of the hydraulic jump and the sequent depth of the jump are the factors that determine the length of the stilling basin. Various methods are used to stabilize asymmetric hydraulic jumps in sudden expanding channels. In this study, the interaction of multiple submerged water jet injection system with S-type hydraulic jump for stabilization and stability of hydraulic jump was laboratory investigated. The different configurations of the jet system were tested with Froude numbers ۷.۴, ۸.۷ and ۹.۵, and finally three optimal configurations were selected as configurations ۱, ۲ and ۳. 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 water jet injection system with S-type hydraulic jump showed that the energy and momentum correction coefficients in channel bed and in all different configurations were significantly reduced. Also, configuration ۲ had a better performance than configurations ۱ and ۳. 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.

کلیدواژه ها:

asymmetric hydraulic jump ، water jet injection system ، expanding channels ، energy loss ، stilling basin.