عنوان مقاله [English]
In the past few decades, the use of spur dikes for stability of the outer banks of rivers and in the bend has attracted the attention of hydraulic engineers. These structures affect the stability of river banks. Setting spur dikes in the flow direction leads to local scour around the spur dike and changes the topography of the stream bed. This paper examines the geometry of the scour hole, the maximum depth of scour, and the bed topography around the T-Shaped spur dike located in a 90 degree bend. The experiments were carried out in an experimental channel with a smooth bend of 90 degrees (having the ratio of the bend radius to the channel width equal to four) under the clear water condition and with sediments having an average diameter of 1.28mm. The effects of parameters like the length of the spur dike and its wing, the location of the spur dike in the bend, and the approach Froude number were studied on the amount of scour. The results showed that by increasing the length of the spur dike, decreasing the wing length of the spur dike, increasing the Froude number, and changing the location of spur dike towards downstream, the dimension of the scour hole increases. New equations for scour parameters at a T-Shaped spur dike are obtained.