Laboratory investigation of the Effect of a Submerged Jet in a Wavy Bed with a Gradually Diverging Cross-section on the Characteristics of Asymmetric Hydraulic Jump

One of the most famous hydraulic phenomena to reduce flow energy is hydraulic jump, which is used downstream of dam overflows in river sections and structures established in irrigation and drainage canals. It is very important to control and reduce the kinetic energy resulting from this phenomenon at smaller distances from the place of formation. Among the examples of depreciation structures, we can mention the roughness of the bed and the construction of stilling basin and making expansion, but it must be said that it causes pressure fluctuations and damage to the bed of the canals and river. The existence of the submerged jet can reduce this pressure fluctuation and change the flow downstream to subcritical. The purpose of this research was to investigate the presence of a submerged jet system on the characteristic of asymmetric hydraulic jump in corrugated beds so that this phenomenon can be controlled and ensure the safety of structures and beds downstream. For this reason, the experiments were carried out in a flume with a fixed peak overflow with a central flow rate range of 26 to 67 liters per second and 3 mutual submerged jet flow rates. This investigation showed that the corrugated bed in the region of gradual expansion has reduced the length of the jump compared to its absence and the changes in the flow depth have also decreased. Also, the impact of the opposite jet in the submerged shape improved this process; So that energy consumption was reduced by 25-30% and jump length by 50%. Therefore, the effective role of this combination of jet system and continuous corrugated bed was shown.