Corresponding Author

Shaker Jalil

Document Type

Research Article


Dissipating high kinetic energy of flow by collide flows with bars has been studied experimentally in open channels. The effect of porosity of strip gaps between bars on the efficiency of the energy dissipation has been examined by using three different porosities of 30%, 40% and 50%. The bars have been fixed in line perpendicular to the flow direction at a relative distance of 80, 110 and 140 times the sluice gate opening for each model. Video record has been used to study the oscillation of water depth on bars face. Captured video frames have been used to measure average flow depth between strip gapes. The experimental results have been analyzed statistically by employing conservation principles. It was found that the major parameters affecting energy dissipation are Froude number and porosity only. The total average percentage of dissipation is 0.7144, and the total average system efficiency is 0.1570. The flow leaves bars device with an average Froude number is 1.14 and pseudo hydraulic jump happens. While the average downstream depth is equal to 0.32 times the sequent depth of classical jump of the same Fr1. The average value of downstream depth deficit percentage (∆Y) is 0.68. It is also observed that much of flow energy is largely dissipated in the upstream part of the collide flow, which is found to be 4.4 times greater than that dissipated in the downstream part. The flow depth oscillation on bars face has an average frequency of 0.31 Hz. Dimensionless relations have been to predict the percentage of energy dissipation with R2 higher than 0.9


energy dissipation, Froude number, hydraulic jump, porosity, bars screen.

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