*Water Structures Enginuring Department Faculty of Engineering, Zagazig University, Zagazig, Egypt
**Irrigation and Hydraulics Department Faculty of Engineering, Ain Shams University, Cairo, Egypt
This paper presents the results of an experlmental lnvestlgatlon on the discharge characteristics of a sluice gate under the effect of different artificial roughened channel beds constructed downstream. Taking the discharge coefficient as the main criterion, we conducted a series of experiments using different shapes of artificial roughness elements (rectangular, hexagonal and cylindrical) fixed In strips as well as staggered forms with a variety of concentrations under a wide range of gate openings and flow condltions. The results were compared with those of other studies involving similar roughness patterns at comparable conditions. Finally, a method is proposed to compute the discharge coefficient for the flow under a sluice gate with roughened bed downstream by considerlng the shape and concentration
