The Effect of Injection Discharge to Reduce the Bend Scour Using Water Injection Technique

One method for reducing scour at river bends is to employ protective structures. In this study, the performance of one of these structures has been investigated using water injection technique. This protective structure is made of a perforated tube. From the two ends of the tube through the ports on it, water is injected into the flume. In this way, a discontinuous water screen is formed and hence the secondary flows are prevented from approaching and eroding the outer bend. The research results using SURFER software show that with the increase in the injection discharge, a reduction occurred in the maximum scour depth in main experiments (in the occurrence sections of these maximums in the control experiments). The place of the maximum scour depth moved from around the outer bank of the bend in the control experiments towards the middle parts of the section in the main experiments, which can positively result in the increase in the navigable width. Moreover, the maximum scour volume decreased with the increase in the injection discharge. On the other hand, the maximum scour volume increased with the increase in the Froude number. The results indicate the more effectiveness of the proposed method in the higher Froude numbers.