Numerical scour modeling around parallel spur dikes in FLOW-3D

Abstract. Spur dikes are some structures which are built in the flow path with the aim of changing flow characteristics in order to bed and bank protection in rivers. These sudden changes in properties caused by the existence of spur dikes, produces erosion and sedimentation around them. In this paper, effects of series of parallel spur dikes have been investigated numerically. For this purpose, by using experimental and numerical research results from technical literatures, the numerical model conducted in FLOW-3D commercial software and the data were compared with experimental and SSIIM results. The results showed that Froude number and the ratio of U/Ucr affect the accuracy of the models. As a result, by discharge increasing, FLOW-3D models need to be calibrated again. Also, by using a calibrated FLOW-3D model, calculation accuracy of the scour depth at the bottom of the spur dikes becomes better and the accuracy level in the modeling of the surface morphology improves 7 percent more than SSIIM software in the bottom of the first spur dike, more than 80 percent at the bottom of the second spur dike and approximately 40 percent at the bottom of the last spur dike.