مشخصات پژوهش

Curved rivers exhibit greater complexity in flow and sediment patterns compared to straight rivers, primarily due to the presence of strong helical flows. The placement of grouped piers in curved sections further amplifies flow complexity .The study aims to evaluate the impact of changing the pier positions in the first half, apex, and second half of the bend on flow velocity variations, flow turbulence in the form of kinetic energy, and changes in the water surface profile using the capabilities of the SSIIM Model. For this purpose, a curved channel with a central angle of 180 degrees and a relative curvature radius of 2 was considered. The bridge piers were arranged in groups of six and positioned at various locations along the bend. The core of the methodology involves an in-depth analysis of velocity contours and turbulence parameters to provide a comprehensive understanding of the flow changes near the piers. The results showed that positioning the piers at 60° leads to a significant increase of approximately 20% in average kinetic energy compared to placements at 90° and 120°. This highlights the crucial impact of pier position on turbulence parameters. The analysis further indicates that vertical velocities peak when piers are aligned at a 120-degree angle, particularly in a central position within the channel. The maximum bed shear stress location is identified at a distance of 1.1 times the pier diameter from its center, directed downstream, and situated at 53% of the channel width from the inner bank. Additionally, the presentation of water surface profile changes at different pier positions along the bend is a key highlight of this research