Scour morphology downstream of submerged block ramps

Abstract

In this study, the effects of geometric parameters, such as the ramp roughness size and the ramp slope on the scour parameters downstream of block ramps, are experimentally investigated for different hydraulic conditions. Scour parameters, such as the maximum scour depth and length and the maximum ridge height and length, are evaluated. Experiments are conducted in clear water conditions (no sediment transport) for different gravel ramp slopes in which different critical flow depths and tailwater depths are examined. The results indicate that the maximum scour depth downstream of a block ramp for different bottom slopes is directly affected by the tailwater depth, independent of the critical flow depth; the scour depth decreases by increasing tailwater depth. A comparison of the results indicates that increasing the roughness of the block ramp leads to a reduction in the maximum scour depth.