Energy dissipation for supercritical flows by using screens with triangular shape openings

Abstract

ABSTRACT In the present study, experiments were conducted in the laboratory to investigate the effectiveness of perforated screens having triangular shape openings in dissipating the energy of supercritical flows. The porosity of the perforated screens was maintained at 45%. Experiments were conducted by placing the screens at an angle α (45°, 75°, 90°, 120°, and 135°) with the upstream direction of supercritical flow. Further, for each of the angular positions, the screens were used both in single and double layers. In the case of the double layer, the two screens were placed at a 2.5 cm gap. The supercritical flow when collided with the screen, a hydraulic jump was created in the immediate upstream of the screen. In all the experiments, the Froude number, F1 of the supercritical flow approaching the screen was varied from 3.16 to 19.26. The relative energy dissipation between the upstream and downstream of the screen was significantly larger than that due to the classical hydraulic jumps. Further, it was found that this relative energy loss varied non-linearly with respect to F1, but the variation was negligible due to screen angles α.