3D SIMULATION OF FLOW AND LOCAL SCOUR AROUND A SPUR DIKE WITH DIFFERENT LOCATION IN MEANDERING CHANNELS WITH DIFFERENT SINUOSITY

The spacing between two spur dikes and the local scour depth are two important considerations in spur dike design. The spacing is related to the downstream separation zone of a spur dike. In meandering channels, the flow field and sediment transport around a spur dike are affected by both the spur dike location and channel sinuosity. The paper employs a 3D model to simulate the flow and sediment transport around a spur dike with different location in meandering channels under different sinuosity. The results show that the downstream separation zone of a spur dike shortens as the spur dike moves downstream or the channel sinuosity decreases. Therefore, the spacing can be adjusted with the location and channel sinuosity for costeffectiveness. The local scour depth around the spur dike tip increases as the spur dike moves downstream and reaches the maximum when the spur dike is placed near the crossover section of a meander, where measures may need to be taken to mitigate the local scour.