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Title
Experimental comparison of flow pattern around convergent-vertical and divergent-vertical pier groups located in a 180 degree sharp bend with streamwise direction
Type Article
Keywords
flow pattern; 180degree sharp bend; 3d velocity; convergent-vertical; divergent-vertical.
Abstract
The flow pattern at the meandering rivers changes to a helical flow. The installation of bridge piers on the meandering river and collision of the flow with pier geometry creates a far more complicated flow. The experiments were performed in a 180-degree bend channel and a radius to curvature ratio of two. The flow pattern around the bridge pier group and along the bend was investigated. The pier groups were installed in convergent-vertical in streamwise direction (CVS) and divergent-vertical in streamwise direction (DVS). The results show that the earliest eddy flows in the convergent-vertical pier groups were formed at near water surface level. According to the findings, the formation of return flow from a 77.5degree angle and at a distance of 35 to 45 percent of the width of the channel from the inner bank happened. However, the return flows were initiated from the 87.5degree and at a distance of 60 to 70% of the width of the channel from the inner bank in the divergent-vertical pier group. The power of secondary flow in convergent-vertical and divergent-vertical pier groups occurred at 85 and 87.5degree sections respectively, and equal to 3.5 and 1.25 times the pier diameter from the center of the piers’ location upstream
Researchers Mohammad Vaghefi (First researcher) ,