| Abstract |
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One of the most common ways of organizing and controlling the side erosion in the bend of rivers is the use of spur dike. The spur dike prevents the strong flow of water along the coast by directing the flow towards the river, preventing the erosion of the river coast. Moreover, the new pattern of flow causes scouring around the spur dike. One of the parameters affecting the scouring in the entrance of spur dikes is the effect of spur dike length. In order to investigate the effect of spur dike length in the bend on the scouring process, experiments were carried out in a laboratory flume with 180 degree bend with R/B=4.7 made of Plexiglas. In this research, by placing the spur dike in a laboratory flume in a 90 degree position with lengths of 8, 10 and 12 cm and with discharge of 28 l/s and a fixed depth of 13 cm, the phenomenon of scouring around the spur dike in a clear water state was investigated.For flume-floor materials, natural sand with uniform granulation with D50=2mm and uniformity coefficient of 1.7 was used. The results of this study show that as the length of the spur dike increases, the depth of scouring around it would also increase. In addition, with increasing flow discharge and positioning of the spur dike in the bend, the dimensions of the hole and the length of stack at the spur dike downstream also increase. |
