Mohammad Vaghefi

Various protective measures are employed to alter flow patterns and mitigate the intensity of vortices and resulting scour around bridge piers. One such method involves the use of submerged vanes positioned upstream of the bridge piers. This study investigated the effects of the changes in the position of the submerged vanes across the channel, as well as distances of the vanes from the bridge pier and from each other with different 100, 50, and 0% overlapping lengths upstream of the pier in a sharp 180° bend by using a SSIIM numerical model. The results demonstrated that the SSIIM model accurately simulated scour with acceptable precision. The upstream submerged vanes significantly impacted the geometric characteristics of the scour cavity around the bridge pier, including maximum scour depth, scour cavity area, and scour cavity volume. On average, the scour depth and sedimentation were reduced by 15.67–50.60% and 6.53–20.41%, respectively. The vanes exhibited a more pronounced effect on reducing the scour cavity volume compared to its area with average reductions of 40.1 and 34.5%, respectively. Increasing the length of overlapping vanes by 50% resulted in a 62.5% reduction in the scour cavity length compared to that of the single-pier model. Additionally, the scour cavity slope was more symmetrical with upstream submerged vanes compared to the single-pier model.