Numerical investigation of flow pattern, erosion and sedimentation around parallel unequal spur dikes under different geometric and hydraulic condition: Numerical analysis

Spur dikes are known as the most popular hydraulic structures which are utilized to reduce shores and river banks erosion. These structures change the flow and sediment transport pattern and so they can control hydraulic conditions and prevent shores erosion and cause sediment trapping. In this paper effects of changes in angles and various arrangement of spur dikes (small to large or vice versa) for group of parallel, unequal, non-submerged and impermeable spur dikes are numerically investigated on flow pattern, bed erosion and sedimentation. Validation of results of Flow-3D numerical model with experimental data, shows the high precision of the numerical model. Also the results show that scour depth in large to small arrangement of the spur dikes and 45 degrees orientation has 55% reduction and in small to large arrangement and 135 degrees orientation has 72% reduction in comparison with group of equal length spur dikes perpendicular to the shore.