Free Hydraulic Jump Due to Parallel Jets

Due to construction, operation, and maintenance difficulties, usually installing very wide sluice gates in open channels is not recommended. Instead, multiple parallel gates have been used in such circumstances, which generate parallel jets. The free hydraulic jump established downstream of two vertical sluice gates with different openings was investigated theoretically and experimentally in this study. The ADV technique was used to record the flow velocity at the tailwater section of a rather large-scale experimental setup. The impact of highly non-uniform velocity distribution of the tailwater section was incorporated in the momentum formulation to develop a relationship for accurately determining the conjugate depth of such a practical case. It was indicated that the momentum correction factor plays a key role to accurately determining the conjugated depths, and it should not be neglected. Considering y0 as the upstream depth and y2 as the tailwater depth, the compiled data of the classical and parallel jets hydraulic jumps revealed that for a given Froude number, higher values of the ratio y0/y2 are required to establish a free hydraulic jump as the gate opening ratio increases. Furthermore, a proper formula was developed to determine the head loss through free parallel jets hydraulic jump.