Modelling the transport of fine suspended sediments
Nguyen, Hoang Ha
Date of Issue2012
School of Civil and Environmental Engineering
The study of fine sediment transport is complicated because it consists of many separate processes such as flocculation if the sediment is cohesive, settling and mixing, deposition, re-suspension and consolidation, etc. In order to model the transport process accurately, all the above-mentioned individual processes and the hydrodynamic characteristics of the flow field need to be correctly modeled, simultaneously. Many studies on the sediment transport process have been conducted in the past; however, gaps exist in our knowledge on this topic and much scope for improvements exists. The present study focuses on some of the fundamental behaviour of sediments in the aquatic environment. These include floc density, dynamic viscosity, and effects of turbulence and sediment concentration on flocculation and settling velocity of (floc) particles. A physically-based parametric approach is developed to improve the existing models; turbulent Reynolds number ( Ret ≡ k2 / εv , where k and ε are the turbulent kinetic energy and its dissipation rate, respectively), which reflects the turbulence level, is used to estimate the strength of flocs and effects of turbulence on the flocculation and settling velocity.
DRNTU::Engineering::Civil engineering::Water resources