Author(s): Zahra Nourmohammadi; Hossein Afshin; Bahar Firoozabadi

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Keywords: Froude number; hydraulic jump; sediment-laden density current; turbidity current; velocity profile

Abstract: The structure of turbidity currents released on a sloping bed below fresh water is investigated. Kaolin is used as a suspended material. Laboratory observations indicate that if a dense layer moves through the channel, the current thickness increases due to a hydraulic jump. This phenomenon occurs under special inlet conditions and has a significant effect on the current structure including velocity profile, current height and bed shear stress. Flows with different inlet Froude numbers based on various inlet concentrations behave more distinctly than those based on different inlet opening heights. Laboratory experiments indicate that an increase in the inlet Froude number causes an increase in the height of sediment-laden density currents and a decrease in the maximum cross-sectional velocity. The effects of the hydraulic jump on the bed shear stress are also investigated. A decrease in this stress and the average velocity is remarkable after the current has passed the jump.

DOI: https://doi.org/10.1080/00221686.2010.543777

Year: 2011