Scour depth and flow pattern or eroding plane jets

Local scour may occur when a hydraulic structure is positioned in a channel with an erodible bed.Herewith investigated experimentally are the erosion and flow pattern due to a water jet passing over a channel bed at the asymptotic (final) state. The development of the scour hole, its maximum scour depth and length, are recorded and compared with available scour-depth relations. Two sets of experiments (see Table 1) were carried out. Set 1 (3 runs) was concerned with measuring the vertical instantaneous velocity distribution in the scour hole. The scour hole at the asymptotic (final) state, t ≈100 [h] was investigated. Set 2 (5 runs) was concerned with studying the physics of scouring. The scour hole at about mid-state, t ≈ 0.5 [h], was investigated; subsequently the scour-hole depth was linearly extended on the semi-log scale to 72 [h]; no velocity measurements were performed. The present data are put in context with some (popular) existing relations; recommended is a modification of some of these relations.