Numerical Study of the Effect of Height of Vertical Screens on Vertical Drop Energy Dissipation

Vertical screens are energy dissipaters that can be used downstream of small hydraulic structures such as vertical drops. In the present study, the effect of the height of the screens on the downstream of the vertical drop has been investigated numerically. For this purpose, three relative heights of 0.2, 0.4 and 0.6 for the screens and the relative critical depth range between 0.12 and 0.42 have been selected. For numerical modeling, Flow-3D software with two turbulence models   and  and three types of meshing has been used. The results showed that the  turbulence model was better performance than    model in comparison with experimental results. Also, the results of using screens with different heights in the downstream of the vertical drop showed that these plates increase the relative energy dissipation and relative depth of the downstream by 176% and 94% respectively compared to the simple vertical drop. Investigating of the increase in energy dissipation efficiency, it can be seen that the screens with relative heights of 0.4 and 0.6 dissipates more energy by reducing the immersion rate of the hydraulic jump compared to the overall mesh plate. Finally, the vertical drop equipped with screen with a relative height of 0.4 with a decrease of 66.3 and 10.3 percent of the Froude number of downstream and an increase of 187 and 2.8 percent relative energy consumption, had the best performance compared to the simple drop and vertical drop equipped with an overall screen, respectively.