Effect of different shapes of holes on energy dissipation through perpendicular screen

The Journal of Environmental studies (JES) 
Vol. (12), 9 pages
Author:Mahmoud 'Mahmoud
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Previous studies have shown that screens may be utilized efficiently for dissipating the energy of water. For the present study, a series of experimental works were conducted to investigate the effect of different shapes of holes with perpendicular screen on the energy dissipation through screens. Water flowing beneath a sluice gate is used to simulate the flow downstream of a hydraulic structure. In the present study, single and double screen arrangements with porosity of 40% and inclination angle of 90° was used. Circular and square holes were used during the study. The major parameters for the present study are upstream flow depth, different shape of holes, location of the screen together with the supercritical upstream flow, Froude number for a range covering from 5.0 to 25. The gate opening simulating a hydraulic structure is adjusted at heights of 1 cm, 2 cm and 3 cm during the experiments work. The results showed that the screen with square holes is better than screen with circular holes. In addition, the results revealed that increase in the relative screen position (X/d) decreases screen effect to dissipate energy, as well as screen thickness has no significant additional contribution on the energy dissipation. As we concluded relations between the performance and efficiency of the system and screen with Froude number at the point G (FrG) and has also been drawing relations between the performance of the system with (FrG) and relations between efficiency of the system and (FrG) as well as between the performance of Perforated screen with (FrG) and the efficiency of Perforated screen with (FrG)


Screen, energy dissipation, circular holes, square holes, hydraulic jump, supercritical flow.