Local scour at curved edge of open-channel junctions

In this study, series of experimental test have been conducted to investigate the effect of downstream edge curvature on the local scour depth at open-channel junctions and river confluence. To do so first using the dimensional analysis, a general non-dimensional equation is developed, then tests conducted for both sharp and round edge under different flow conditions. The results of this study indicate that as the radius of curvature increases, the maximum local scour decreases significantly and the location of maximum scour hole depth shifted downstream and toward the center of the main channel. The results for curvature ratio equal to 0.28, 0.5 and 1.0 and for the discharge ratio equal to 0.2 indicate that the scour depth decreases up to 40, 68 and 100% respectively compare to the sharp edge confluence under the same flow conditions. A new relation has been developed for prediction of scour depth for round edge open-channel junctions.