Mohammad Vaghefi

This study presents an experimental investigation on the influence of flow velocity and pier group positioning parameters on scour characteristics in meandering channels. The experiments were conducted at different flow velocity ratios relative to the critical velocity, specifically 0.9 and 0.98. The findings reveal that an increase in the U/Uc ratio from 0.9 to 0.98 results in a notable rise in the maximum scour depth around pier groups situated at various positions. Regardless of the channel geometry, the maximum scour depth consistently occurs when the pier group is positioned opposite the individual piers. Furthermore, the scour depth is significantly maximized when the pier group is placed at the 225-degree position. The results further indicate that, in all cases, the maximum scour volume increases for pier groups and single-pier configurations located in the lower bend compared to the upper bend. Additionally, transitioning from single-pier arrangements to pier groups at U/Uc = 0.98 yields a considerable increase in the maximum scour volume at positions of 180°, 225°, 270°, and 315°, with respective enhancements of 100%, 25%, 15%, and 40%. The maximum scour hole volume is consistently observed at the 270-degree position for both single-pier and pier group configurations.