Regime shifts in the Changjiang (Yangtze River) Estuary: The role of concentrated benthic suspensions

Channel deepening often triggers positive feedback between tidal deformation, sediment import and drag reduction, which leads to the regime shift in estuaries from low-turbid to hyper-turbid state. In this study, a transition in profiles of suspended sediment concentration (SSC) is hypothesised by including a positive feedback loop of...

An integrated optic and acoustic (IOA) approach for measuring suspended sediment concentration in highly turbid environments

Accurate measurement of suspended sediment concentration (SSC) in highly turbid environments has been a problem due to optical or acoustic signal saturation and attenuation. The saturation returns a limited measurement range, and the attenuation raises an ambiguity problem that a low optical or acoustic output could mean a low or a high SSC....

Entraining Flow of a Concentrated Benthic Suspension: Computations with the Prandtl Mixing-Length Model

The Prandtl mixing-length model of turbulent exchange of mass and momentum is applied to calculate the entrainment of overlying water into a layer of suspended fine sediment at a horizontal bed. In the field the flow and turbulence in such a concentrated benthic suspension (CBS) are driven by a streamwise pressure gradient resulting from the...

Laminarisation in Flows of Concentrated Benthic Suspensions: Computations with a Low-Re Mixing-Length Model

In quiescent water bodies that form part of estuarine or coastal water systems, such as harbours and access channels, fine sediments may deposit to form concentrated benthic suspensions (CBS). The flow velocities in these mud layers may become low, and the viscosities may become large, so that the Reynolds number decreases below a critical value...