Department of Civil Engineering, Islamic Azad University of Shahr-e-Qods, Tehran, Iran.
Department of Civil Engineering, Shomal University, Amol, Iran.
Department of Civil Engineering, Tarbiat Modares University, Tehran, Iran.
Water Engineering Research Institute, Tarbiat Modares University, Tehran, Iran.
Constructing the spur-dikes is one the most efficient methods for protecting river banks. The spur-dike in the flow path leads to local scour around this structure. Scour around the spur-dike is one the major problems that might endanger the stability of the structure. Therefore, estimating the scour around this structure based on the flow condition and geometry of the spur- dike is highly important. The experiment was conducted in laboratory flume 6m long, 0.45 m width and 0.45 m deep and with median diameter of particle size 1.48 mm and the maximum local scour around the direct upright and trapezoidal spur-dike (with slope side) and the effect of Froude number and spur-dike side slope on geometry of local scour are investigated. According to the results, by increasing the Froude number and spur-dike side slope, the maximum scour depth and hole dimension of scour is increased, also sedimentation length is increased but its height is decreased and the amount of bed changes toward downstream is increased.