Experimental Study on Scour Due to a Circular Offset Jet in Cohesive Sediment

Abstract: In this study the effect of Froude number and tailwater depth on the scour profile due to a 3d circular offset jet are investigated experimentally. Experiments were conducted in a channel 8 m long, 0.8 m height and 0.61 m width. For generating jet flow, a pipe with 1 cm inside diameter and 1.5 m long were used. A sediment mixture (80% cohesive less sand with median size of 0.4 mm and 20% cohesive sediment) was used as the bed material. Experiments were conducted using three tailwater depths (i.e. 10, 15 and 20 cm) and four pipe Froude numbers (i.e. 3, 5, 7 and 9). The dimensions of scour hole including depth of scour, width of scour hole, length of scour hole and ridge height downstream of scour hole were measured. Results of experiments are reported in this paper.