Three-dimensional Flow and Sediment Transport at River Mouths


Book Description

Three-dimensional flow processes of a river emptying into the sea were analyzed. The basic equations which were derived to describe this flow included the effects of buoyancy caused by density differences between fresh and salt water, inertia of river and coastal currents, and differences in hydrostatic head throughout the mixing region. Turbulence effects were included through an appropriate eddy viscosity model. Combinations of river stages and tidal currents were represented as systems of steady-state flow fields. A numerical procedure was developed and implemented on a digital computer for the solution of the equations. This numerical procedure is classified as an asymptotic time-dependent finite-difference technique but includes certain features of a relaxation technique. Computed flow fields were used to track a distribution of nominal particles representing the suspended load of the river as determined from field data. Deposition of these particles was primarily governed by convective processes and particle settling velocities, which included the effect of a local turbulence level. Deposition rates were used to compute deltaic growth. Results were compared to a delta for which experimental data were available. (Author).




Three-dimensional Numerical Simulation of Mobile-bed Hydrodynamics


Book Description

"This report describes the theoretical principles of three-dimensional sediment transport and bed-evolution processes, and numerical solution of the appropriate governing equations. It also includes technical documentation and user's instructions for the sediment-operations program module developed as an integral part of the CH3D code."--P. ii.










Three-Dimensional Flow in Tidal Channels


Book Description

The objective of this project is to improve understanding of shallow estuarine flows and sediment transport by collecting and analyzing measurements of three-dimensional flow structure in tidal channels and adjacent tidal flats.










Coastal Sedimentary Environments


Book Description

The zone where land and sea meet is composed of a variety of complex environments. The coastal areas of the world contain a large percentage of its population and are therefore of extreme economic importance. Industrial, residential, and recreational developments, as well as large urban complexes, occupy much of the coastal margin of most highly developed countries. Undoubtedly future expansion in many undeveloped maritime countries will also be concentrated on coastal areas. Accompanying our occupation of coasts in this age of technology is a dependence on coastal environments for transportation, food, water, defense, and recreation. In order to utilize the coastal zone to its capacity, and yet not plunder its resources, we must have extensive knowledge of the complex environments contained along the coasts. The many environments within the coastal zone include bays, estuaries, deltas, marshes, dunes, and beaches. A tremendously broad range of conditions is represented by these environments. Salinity may range from essentially fresh water in estuaries, such as along the east coast of the United States, to extreme hypersaline lagoons, such as Laguna Madre in Texas. Coastal environments may be in excess of a hundred meters deep (fjords) or may extend several meters above sea level in the form of dunes. Some coastal environments are well protected and are not subjected to high physical energy except for occasional storms, whereas beaches and tidal inlets are continuously modified by waves and currents.




Computational River Dynamics


Book Description

Comprehensive text on the fundamentals of modeling flow and sediment transport in rivers treating both physical principles and numerical methods for various degrees of complexity. Includes 1-D, 2-D (both depth- and width-averaged) and 3-D models, as well as the integration and coupling of these models. Contains a broad selection