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CH3D-SED Numerical Modeling System
Entry ID: CHL-CH3D-SED
Abstract: CH3D-SED is the newly developed mobile bed version of CH3D-WES. It is being
utilized to investigate sedimentation on bendways, crossings, and
distributaries on the lower Mississippi and Atchafalaya Rivers. These
applications address dredging, channel evolution, and channel training
A boundary fitted, non-orthogonal, finite difference approximation in ... the
horizontal plane and a sigma-stretched approximation in the vertical direction
are used for the approximations of the governing equations.
The hydrodynamic model solves the depth averaged Reynolds approximation of the
momentum equation for velocity, and the depth averaged conservation of mass
equation for water surface elevation. The three dimensional velocity field is
determined by computing the deviation from the depth averaged velocity by
solving the conservation of mass equation in conjunction with a k-e closure for
vertical momentum diffusion.
Sedimentation computations are based on a two dimensional solution of the
conservation of mass for the channel bed, and three dimensional
advection-diffusion equation for suspended sediment transport.
The sediment transport algorithms independently account for the movement of
sediment as either bed load or suspended load, as well as the exchange of
sediment between these two modes of transport.
The model is also generalized for application to mixed grain size sediments,
with appropriate bed material sorting and armoring routines. The formulation to
a user specified multiple grain size distribution uniquely allows the
simulation of erosion, entrainment, transport, and deposition of contaminated
sediments on the bed and in the water column. A contaminated sediment
associated with a given grain size can be independently accounted for by
applying a small dimensional perturbation from the reference grain size. This
perturbation will have negligible effects on sediment mobility characteristics.
Since each grain size specification is independently tracked, however, tracking
of zones of contaminated bed material is possible.
Use Constraints Model development and application is possible through formulating a cooperative
research agreement with your organization.
Creation and Review Dates