Hindered settling of sand-mud flocs mixtures: From model formulation to numerical validation
Abstract
Mixtures of non-cohesive and cohesive sediment are frequently encountered in natural environments such as estuaries. Depending on the concentration of both species, mixed sediment can record segregation effect or not, behaves like a non-cohesive sediment or like a cohesive sediment. The present study deals with the segregation effect between mud flocs and sand grains during hindered settling. Simulations of this process under various conditions of mixture are proposed by using two coupled mass conservation equations which are solved by a high order numerical model. Specific closure equations are proposed herein for the hindered settling of sand-mud mixed sediment. Comparisons between simulations and experiments are presented on vertical concentration profiles during the segregation process. Obviously, the model enables the description of hindered settling for pure non-cohesive (or pure cohesive) case and the segregation for bi-disperse suspensions. © 2012 Elsevier Ltd.
Keywords
ADER
Bi-disperse
Discontinuous Galerkin
Hindered settling
Sand-mud mixture
Closure equations
Cohesive sediments
Concentration profiles
Coupled mass
Mixed sediments
Model formulation
Mud flocs
Natural environments
Numerical validations
Sand grains
Segregation effects
Segregation process
Galerkin methods
Mixtures
Sand
Sediments
Sedimentology
cohesion
dispersion
Galerkin method
mixing
mud
numerical model