Numerical Study of the Effect of Submerged Spur Dike Length on the Flow Pattern in a Straight Open Channel

One of the important purposes of the river engineering is to protect the river banks from erosion phenomenon and to prevent the shifting of the main channel path. Spur dike is a hydraulic structure which has a lot of applications for stabilizing riverbanks and increasing water depth. Owing to the widespread use of thisstructure , it is important to understand the flow patternaround it.Since flow pattern around a spur dike is complex and fully 3D, hence a 3D simulation has been done in this study. FLOW-3D software was employed to simulate the flow around a submerged spur dike. VOF method was used for free surface simulation and RNG k-εmodel was used for turbulence modeling. Based on comparison of the numerical and experimental results for stream wise velocity components and flow depths, it was concluded that the numerical model could simulate the flow passing the submerged spur dike. Then the effect of the spur dike length on the velocity profiles, free surface and flow pattern was studied. Based on the results, the maximum stream wise velocity in the nose of the spur dike increased with increase of spur dike length. This velocity showed about 24% and 59% increase in case of the spur dike with 0.1m and 0.4m length, respectively. Also, the flow depth incr eased with increase of the spur dike length