EXPERIMENTAL STUDY ON THE TRANSFORMATION AND MIGRATION OF BARS UNDER UNSTEADY FLOW CONDITIONS

Abstract

 This research focuses on the transformation process of alternate bars during floods. The series of flume experiments were conducted to investigate the role of the period that flood discharge rising and decreasing. Firstly, unsteady flow supply to movable bed, alternate bars form as initial condition. And 4 cases were set considering unsteady condition that discharge change, so that we could search the change of bar formation and migration. We demonstrated that the decreasing phase of flood discharge is more critical for bar transformation compared to the rising phase. In contrast, the rising phase of flood discharge has a greater influence on bar migration, with higher rates of discharge increase significantly accelerating migration speed.