Influence of layout angles on river flow and local scour in grouped spur dikes field

The flow properties, sediment moving and geomorphology in the grouped spur dikes field have always been of interest in river engineering. In this paper, a 3D numerical model is employed to investigate the flow motion and riverbed scouring around grouped spur dikes with different layout angle styles. Series of flume experiments are introduced to verify this model's reliability before its application on the simulation of the downward-angled spur dikes case and normal-angled spur dikes case respectively, and detailed comparative analyses on the flow intensity, vortex patterns and local scour are made for these two layout angle styles respectively, in which the similarities and differences could both be found. Then the influence of flow conditions, sediment parameters and spur dike layout angles on the maximum scour depth and their coordinates are discussed through additional simulations, while the different correlations show between the maximum scour depths with these three factors. Then the simulation of flood passage through the spur dike fields is conducted, which could not only provide river hydrological information but also offer guidance for the hydraulic structure safety.