Author(s): Heqing Huang IAHR Member; Jasim Imran IAHR Member; Carlos Pirmez

Linked Author(s):

Keywords: Depth-averaged model; Gravity flow; Nondimensional parameter; Shape factor; Turbidity current

Abstract: The nondimensional parameters involved in a four-equation depth-averaged model of gravity flows have been studied using a vertical structure resolving numerical model at both field and laboratory scales. The main findings of this study are: (i) Water entrainment coefficient of gravity flows depends strongly on the bed slope, but compared with the bulk Richardson number, it has a weak dependence on entrainment/deposition at the bottom boundary; (ii) Depositional flow at laboratory scale may become erosive and thus change its characteristics significantly at the field scale if scaled by the densimetric Froude number; (iii)Values of the shape factors of depth-averaged models deviate from those approximated by the top-hat assumption, but they vary little with changes in channel bed slope, inflow, erosion/deposition at the bottom boundary, or scale. Two different sets of shape factors are recommended, one for conservative density flows and another for turbidity currents.

DOI: https://doi.org/10.1080/00221686.2009.9522021

Year: 2009