Non-erodible horizontal aprons are employed downstream of hydraulic structures to dissipate the kinematic energy and to control the downstream scouring. This paper experimentally explored the effect of the height of roughness elements and height of corrugation aprons on the scour geometry downstream of submerged hydraulic jumps. In the present study, 180 experimental tests were performed on four different aprons with roughness heights of 22, 29, 41 and 51 mm. Two different types of roughness were considered, (roughness due to natural particle with uniform grain sizes and due to U-shaped corrugated aprons), under different flow conditions. A case of smooth apron was included to estimate the influence of both roughness types on the scour hole dimensions. Obtained results were analyzed and graphically presented and simple formulae were developed to estimate the maximum scour length, depth and the scour hole dimensions. The results indicated that as the roughness height increases, a significant reduction in the scour dimensions occurred. Nature rough basins produce minimum scour hole in comparison with the corrugated basins. |
