Modelling of Sand Bars in Coastal Environments
A mathematical model describes the formation of sand bars by progressive wind-generated waves. The model decomposes into several constituents linked together in a two step morphological...
A Method to Treat Incident Wave Condition in Shallow Water Equation
A method to consider open boundary condition of the shallow water equation to analyze water surface wave and tide is employed in the finite element anaysis. This can be done by considering...
Wave?Current Interaction and Sediment Transport
The paper reports on a study into whether a close relationship between the mixing (diffusion) coefficient for the sediment, ?s, and the mixing (diffusion)...
Using Sediment-Threshold Theories in Waves and Currents
Fundamentally different threshold-of-motion theories were applied to sand transport in two different coastal environments. Several recommendations for threshold application were reached....
Transport of Grain-Water Mixture by Waves
The numerical modelling of the morphological changes of coastal regions is hampered by the multiplicity of empirical sediment transport formulae. The paper discusses the modes of transport...
The Beginning of Sediment Transport as a Probability-Problem
Sediment transport only takes place when the action of flow (shear stress, velocity) exceeds a critical value. The limit between rest and movement can be given as critical flow velocity,...
Instability of Bed-Surface Composition Due to Sorting Process in a Stream Composed of Sand and Gravel
Wavy patterns of sorting are often observed in a stream composed of sand and gravel, and they are regarded as instability of bed-surface composition due to selective bed-load transport...
Mid-Scale Laboratory Tests on a Two-Dimensional Movable-Bed Sand Model
A two-dimensional physical model was used to simulate wave-induced scour in front of a concrete dike sloped at 1:4. The tests were conducted at the U.S. Army Engineers Waterways Experiment...
The Structure of Intermittent Sand Suspension Events Under Mild Wave Conditions
Nearshore sedimentation processes are being actively investigated through a series of research projects at the University of Miami. Quantitative measurements of waves, currents, and suspended...
Bank Failure and Erosion on the Illinois Waterway
In 1988, bank failure and erosion on the Illinois Waterway were evaluated. Banks were inspected from the air and from a motor vessel; thirty-one sites were examined in detail. Severe erosion...
Boundary Conditions of Tidal Model at River Mouth
A small grid is required to schematize irregular shape of shoreline in the vicinity of river mouth which limits the modeling area to be small. Tidal records along the boundary show no...
Sorting of Mixed Sand on a Two-Dimensional Beach
A numerical method is developed to predict temporal variations of the sea bed topography and the bed-material composition. The predicted results are compared with the measurements in a...
Hydraulic Mechanisms of Riverbank Erosion
Recent efforts are described to develop an improved understanding of bank failure due to piping in noncohesive layers in riverbanks. The efforts included field surveys and laboratory tests....
Cellular Automaton Simulation of Viscous Free Surface Fluid Dynamics
It has been demonstrated elsewhere that the simple interaction of a two dimensional field of discrete particles traveling on a regular lattice yields large scale behavior closely approximating...
Analysis of Pumping Station and Force Main Networks
A computer program to simulate the performance of wastewater pumping station and force main networks is discussed. Results are presented which compare system performance for steady and...
Closed Conduit Vapor Lock
Closed conduit vapor lock can occur when a cross country liquid pipeline is displaced with a gas and the gas is allowed to get ahead of the liquid/gas interface. A simple hydraulic model...
Verification of Local Modes in a Two-Dimensional Tidal Model
Based on a generalized model equation, a two-dimensional hybrid finite element model has been developed to study tidal waves of incompressible, homogeneous fluid in rotational flows. In...
Risk-Cost Principles for Dam Safety Analysis
The purpose of this paper is to present the principles and issues of risk-cost analysis as they have evolved in the evaluation of dam safety improvements. The paper also reviews some results...
Design of Expansions for Sub-Critical Open Channel Flow
Expansions for open channel flow at sub-critical velocity are required whenever it is necessary to reduce the velocity of flow from a structure which discharges into an erodible channel....
Technical Considerations in Numerical Modeling of Pressure Reducing Valves in Water Distribution Systems
In large water distribution networks, pressure reducing valves (PRVs) are common water appurtenances. However, there are difficulties in representing them when using the Hazen-Williams...
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