Numerical Investigation of Average Velocity Distribution and Shear Stress Flow at 90 Degree Mild Bend for Protection of Coastal

Spurs dike structure are used to protect coastal and prevent erosion. The importance of these structures in the outer bank of the rivers becomes more significant, as secondary streams are involved in this area and consequently the coast erodes. The purpose of the present study is to do a numerical investigation of velocity distribution and shear stress with spur dike located at 90 degree mild bends. In this study, two lengths of spur dikes equivalent to 15 and 25 percent of width of Experimental canal, two distance equivalent to 3 and 7 times of spur dike at two depth 3 and 9 cm to bed at flume with , bed width B=0.7 m and depth water 0.12m are analyzed and investigated. For calibration of remembered model, experimental velocity data measurements by Bakhtiari et al (2012) are used. The results of the study show that, spur dikes at bend, used the maximum of average velocity inverted to inner bend at inlet section of bend and then diverted to middle of canal and finally transport to 1/3 end of bend to the outer bend . About shear stress distribution, the extracted results are similar to distribution of average velocity and the investigation shows that geometry and position of spur dike don’t affect the maximum shear stress distribution.