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Articles 1 - 24 of 24
Full-Text Articles in Hydraulic Engineering
Metadata For Describing Water Models, Mohamed M. Morsy, Jonathan L. Goodall, Christina Bandaragoda, Anthony M. Castronova, Jane Greenberg
Metadata For Describing Water Models, Mohamed M. Morsy, Jonathan L. Goodall, Christina Bandaragoda, Anthony M. Castronova, Jane Greenberg
Anthony Castronova
Computer models are widely used in hydrology and water resources management. A large variety of models exist, each tailored to address specific challenges related to hydrologic science and water resources management. When scientists and engineers apply one of these models to address a specific question, they must devote significant effort to set up, calibrate, and evaluate that model instance built for some place and time. In many cases, there is a benefit to sharing these computer models and associated datasets with the broader scientific community. Core to model reuse in any context is metadata describing the model. A standardized metadata …
Session E8: Can We Measure Cumulative Effects Of Hydro-Power On Migratory Fish? Development Of A Cumulative Effects Model Framework, Iain Stewart-Russon, Simon Palmer, David Fraser
Session E8: Can We Measure Cumulative Effects Of Hydro-Power On Migratory Fish? Development Of A Cumulative Effects Model Framework, Iain Stewart-Russon, Simon Palmer, David Fraser
David Fraser, PhD
Abstract: The Environment Agency provides guidance for run-of-river hydropower schemes in England, but concerns about small effects from multiple single schemes led to a project to determine how these can be assessed and to test an approach on migratory fish populations. We developed a model to assess the impact of multiple hydropower schemes. The model forecasts catchment-scale cumulative effects using three elements: hydropower scheme, spatial fish population and fish life cycle. The scheme element includes effects that are important to migratory fish and those that can be quantified. These are: 1) impediment to up- and downstream migration; 2) alleviation of …
A Computer Program For Optimal Control Of Water Supply Pump Stations: Development And Testing, Donald V. Chase
A Computer Program For Optimal Control Of Water Supply Pump Stations: Development And Testing, Donald V. Chase
Donald V. Chase
This report presents an optimal control methodology designed to reduce the electrical consumption and operating costs at Army water supply pumping stations. The methodology, contained in a computer program called Optimal Control of Pumping Stations (OCOPS), enables water utility managers and operators to reduce the electrical consumption at pumping stations while maintaining adequate storage and system pressures for fire protection. OCOPS can be applied to any water distribution system and is not limited to any number of pumps, pump stations, or storage tanks within the system. The optimal control strategy developed is based on electricity unit charges, but can be …
Water Distribution Modeling, Thomas M. Walski, Donald V. Chase, Dragan A. Savic
Water Distribution Modeling, Thomas M. Walski, Donald V. Chase, Dragan A. Savic
Donald V. Chase
To effectively use water distribution models, the engineer must be able to link knowledge of basic hydraulic theory and the mechanics of the program with that of the operation of real-world systems. Water Distribution Modeling does just that. Written by industry experts, it provides a practical resource for engineers and modelers that goes well beyond being a how-to guide for typing data into a computer program. It contains straightforward answers to common questions related both to modeling and to distribution systems in general. This textbook walks the practicing engineer or student through the modeling process from start to finish — …
Failed Cyberdefense: The Environmental Consequences Of Hostile Acts, Jan Kallberg, Rosemary A. Burk
Failed Cyberdefense: The Environmental Consequences Of Hostile Acts, Jan Kallberg, Rosemary A. Burk
Rosemary A. Burk
A failed cyberdefense can have wider effects than discussed in earlier debates of potential consequences of a cyberattack. The need for cyberdefense to protect the environment has not drawn the attention it deserves as a national security matter. Adversarial nations are covertly pursuing methods to damage and disrupt the United States in a cyberconflict in the future. The president of the United States noted this in Sustaining U.S. Global Leadership: Priorities for 21st Century Defense: Both state and non-state actors possess the capability and intent to conduct cyberespionage and, potentially, cyberattacks on the United States, with possible severe effects on …
Climate Change And Hydrological Risks Related To Railway Infrastructure In Northern Regions, Barry A. Palynchuk Phd
Climate Change And Hydrological Risks Related To Railway Infrastructure In Northern Regions, Barry A. Palynchuk Phd
Barry A. Palynchuk PhD
In this paper, the authors discuss the possible consequences of global warming on northern hydrology and their impacts on railway drainage infrastructure. How can we change actual design approaches, methods and standards to adapt, to reduce vulnerability and to improve resilience to climate change? Under current climate conditions, snow, ice and permafrost play a dominant role in the water balance in cold regions. Three areas can be distinguished: regions of continuous permafrost, regions of discontinuous permafrost and permafrost-free regions. To predict the potential climate change impacts on each region, the spatial analog and the climate variability analog approaches can be …
Assessment Of The Effects Of Marine Tides On Coastal Infrastructure, Barry A. Palynchuk Phd, Michel-Olivier Huard M.A.Sc, Zoubir Bouazza Phd, Evelyn Liu M.A.Sc
Assessment Of The Effects Of Marine Tides On Coastal Infrastructure, Barry A. Palynchuk Phd, Michel-Olivier Huard M.A.Sc, Zoubir Bouazza Phd, Evelyn Liu M.A.Sc
Barry A. Palynchuk PhD
A combined rail system and port facility development was investigated in West Africa. The principal components are 700 km of single track heavy-haul railway and a new deepwater port near the Atlantic Ocean. A significant challenge for the project is the assessment of the tidal effects for structures located on coastal rivers whose delta is influenced by the Atlantic tides. The flow in Delta is multidimensional and assessment of hydrodynamics in this context requires physical modeling or numerical modeling. Such modeling requires more reliable data on topography, bathymetry and boundary conditions. A simplified hydrodynamic model was used for the estimation …
Wave Transmission And Water Setup Behind An Emergent Rubble-Mound Breakwater, Lorenzo Cappietti, Douglas Sherman, Jean Ellis
Wave Transmission And Water Setup Behind An Emergent Rubble-Mound Breakwater, Lorenzo Cappietti, Douglas Sherman, Jean Ellis
Jean Taylor Ellis
No abstract provided.
Canal Structure Automation Rules Using An Accuracy-Based Learning Classifier System, A Genetic Algorithm, And A Hydraulic Simulation Model. I: Design, J. E. Hernandez, G. P. Merkley
Canal Structure Automation Rules Using An Accuracy-Based Learning Classifier System, A Genetic Algorithm, And A Hydraulic Simulation Model. I: Design, J. E. Hernandez, G. P. Merkley
Jairo E. Hernández
Using state-of-the-art computational techniques, a genetic algorithm (GA) and an accuracy-based learning classifier system (XCS) were shown to produce optimal operational solutions for gate structures in irrigation canals. An XCS successfully developed a set of operational rules for canal gates through the exploration and exploitation of rules using a GA, with the support of an unsteady-state hydraulic simulation model. A computer program which implemented the XCS was used to develop operational rules to operate all canal gate structures simultaneously, while maintaining water depth near target values during variable-demand periods, and with a hydraulically stabilized system when demands no longer changed. …
Canal Structure Automation Rules Using An Accuracy-Based Learning Classifier System, A Genetic Algorithm, And A Hydraulic Simulation Model. Ii: Results, J. E. Hernández, G. P. Merkley
Canal Structure Automation Rules Using An Accuracy-Based Learning Classifier System, A Genetic Algorithm, And A Hydraulic Simulation Model. Ii: Results, J. E. Hernández, G. P. Merkley
Jairo E. Hernández
An accuracy-based learning classifier system (XCS), as described in a companion paper (Part I: Design), was developed and evaluated to produce operational rules for canal gate structures. The XCS was applied together with a genetic algorithm and an unsteady hydraulic simulation model, which was used to predict responses to gate operation rules. In the tested cases, from 100 to 2,000 XCS simulations, each involving thousands of hydraulic simulations, were required to produce satisfactory rules. However, the overall fitness of the set of rules increased monotonically as XCS simulations progressed. Initial fitness started at an arbitrary value, and rules increased in …
Masw Tests For Detection Of Decayed Buried Timber Within Railway Embankments, Barry A. Palynchuk Phd, Chris Bunce Phd, Steve Sather M.Eng
Masw Tests For Detection Of Decayed Buried Timber Within Railway Embankments, Barry A. Palynchuk Phd, Chris Bunce Phd, Steve Sather M.Eng
Barry A. Palynchuk PhD
No abstract provided.
Study Of A Nanoscale Water Cluster By Atomic Force Microscopy, Manhee Lee, Baekman Sung, Nicole N. Hashemi, Wonho Jhe
Study Of A Nanoscale Water Cluster By Atomic Force Microscopy, Manhee Lee, Baekman Sung, Nicole N. Hashemi, Wonho Jhe
Nastaran Hashemi
We present a novel method for investigating a nanometric cluster of water molecules, which includes the formation and manipulation of nanometric water, and the measurement of its mechanical properties. The atomic force microscope based on the quartz tuning-fork sensor is employed to form and manipulate the nanometric water, and the theoretical tool of amplitude-modulation atomic force microscopy is used to obtain the elasticity, viscosity and dissipation energy of it. With high vertical resolution less than [similar]0.1 nm and high force sensitivity of [similar]0.01 N m−1, this tool facilitates the stable formation and manipulation of a nano-water cluster ([similar]104 molecules) in …
The Nonlinear Dynamics Of Tapping Mode Atomic Force Microscopy With Capillary Force Interactions, Nicole N. Hashemi, H. Dankowicz, M.R. Paul
The Nonlinear Dynamics Of Tapping Mode Atomic Force Microscopy With Capillary Force Interactions, Nicole N. Hashemi, H. Dankowicz, M.R. Paul
Nastaran Hashemi
We study the nonlinear dynamics of a tapping mode atomic force microscope with tip-surface interactions that include attractive, repulsive, and capillary force contributions using numerical techniques tailored for hybrid or discontinuous dynamical systems that include forward-time simulation with event handling and numerical pseudo-arclength continuation. We find four branches of periodic solutions that are separated by windows of complex and irregular dynamics. The branches of periodic solutions end where the cantilever comes into grazing contact with event surfaces in state space, corresponding to the onset of capillary interactions and the onset of repulsive forces associated with contact. These windows of irregular …
Approaches To Mitigating Decayed Buried Timber Within Railway Embankments, Barry A. Palynchuk Phd
Approaches To Mitigating Decayed Buried Timber Within Railway Embankments, Barry A. Palynchuk Phd
Barry A. Palynchuk PhD
During the last three years, several sinkholes have been observed along CPR railway lines in Southern Ontario. The sinkholes have formed as a result of the decay of buried timber trestles in railway embankments. Although it has not occurred the sinkholes could result in hazardous changes in track geometry under load. This study summarizes the site investigation results and remedial methods implemented at five sites in southern Ontario. Remedial methods include placement geosynthetic reinforcement, soil-cement column reinforcement and grouting of voids at the trestle bents. The design, installation methods and construction constraints for the remedial options are described in this …
Small-Scale Structure Of Strongly Stratified Turbulence, Jin Hwan Hwang, Chris R. Rehmann
Small-Scale Structure Of Strongly Stratified Turbulence, Jin Hwan Hwang, Chris R. Rehmann
Chris R. Rehmann
The small-scale structure of turbulence subjected to strong stratification is analyzed with rapid distortion theory to evaluate the performance of formulas for predicting dissipation of turbulent kinetic energy and dissipation of scalar variance. The approach is restricted to weak turbulence in strong stratification, like that in the thermocline or the abyssal ocean. Flows with and without mean shear are considered. For unsheared turbulence, the small scales are axisymmetric about the vertical axis, as others have previously assumed. The calculations here complement and extend previous work because they can be used to compute errors in dissipation estimates, develop simpler formulas, and …
Comparison Between Analytical Probabilistic And Computer Simulation Models, Using Current Design Examples, Barry A. Palynchuk Phd
Comparison Between Analytical Probabilistic And Computer Simulation Models, Using Current Design Examples, Barry A. Palynchuk Phd
Barry A. Palynchuk PhD
Closed form analytical expressions have been developed to solve several basic problems related to the hydrologic design of storm water management facilities. The collection of these analytical expressions is referred to as the Analytical Probabilistic Storm Water Models (APSWM). APSWM can be used as an alternative to the design storm simulation models in the design and analysis of storm water management facilities. In this paper, a comparison is made between APSWM and design storm simulation models as applied to an actual design case. Conventional outputs such as runoff volume, peak discharge, and peak discharge from detention ponds are reviewed and …
Laboratory Measurements Of Differential Diffusion In A Diffusively Stable, Turbulent Flow, P. Ryan Jackson, Chris R. Rehmann
Laboratory Measurements Of Differential Diffusion In A Diffusively Stable, Turbulent Flow, P. Ryan Jackson, Chris R. Rehmann
Chris R. Rehmann
Laboratory experiments were performed to determine the conditions under which differential diffusion occurs and to evaluate its effect on the mixing efficiency. Diffusively stable profiles of temperature and salinity were stirred steadily by horizontally oscillating vertical rods. The two-component stratification ensures that both scalars experience the same stratification and forcing, or Richardson and Reynolds numbers. The eddy diffusivities KT and KS, for temperature and salinity, were estimated by fitting theoretical solutions of diffusion equations to measured profiles, and the mixing efficiency was computed as the ratio of the potential energy change during a stirring interval to the work done in …
Kinematic Effects Of Differential Transport On Mixing Efficiency In A Diffusively Stable, Turbulent Flow, P. Ryan Jackson, Chris R. Rehmann
Kinematic Effects Of Differential Transport On Mixing Efficiency In A Diffusively Stable, Turbulent Flow, P. Ryan Jackson, Chris R. Rehmann
Chris R. Rehmann
If temperature and salinity are mixed at different rates, the mixing efficiencies in flows with the same stratification and forcing can vary if the contributions of temperature and salinity to the density differ. Two models are used to examine the effect of differential transport of salt and heat on the mixing efficiency. The first model assumes constant eddy diffusivities for heat and salt and examines the effect of the density ratio Rρ = αΔT/βΔS and the diffusivity ratio d = KS/KT on the mixing efficiency. The model predicts that the effect of differential transport can be as large as that …
Systematic Microstructure Variability In Double-Diffusively Stable Coastal Waters Of Nonuniform Density Gradient, Timothy F. Duda, Chris R. Rehmann
Systematic Microstructure Variability In Double-Diffusively Stable Coastal Waters Of Nonuniform Density Gradient, Timothy F. Duda, Chris R. Rehmann
Chris R. Rehmann
Conductivity microstructure, water velocity, and stratification were measured during a tow-yo transect near the New England shelf/slope front in early August 1997. Velocity data were collected with an acoustic Doppler profiler on the ship. The other data were collected with a towed platform. Estimates of χ, the rate of dissipation of temperature variance, were computed from the conductivity data with vertical resolution of 0.3 m. Relationships between χ and shear, temperature gradient, buoyancy frequency (N), and gradient Richardson number (Ri) were explored, with special focus on measurements taken in waters stable to double-diffusive processes (to avoid ambiguity of interpretation) and …
Scaling And Parameterization Of Stratified Homogeneous Turbulent Shear Flow, Lucinda H. Shih, Jeffrey R. Koseff, Joel H. Ferziger, Chris R. Rehmann
Scaling And Parameterization Of Stratified Homogeneous Turbulent Shear Flow, Lucinda H. Shih, Jeffrey R. Koseff, Joel H. Ferziger, Chris R. Rehmann
Chris R. Rehmann
Homogeneous sheared stratified turbulence was simulated using a DNS code. The initial turbulent Reynolds numbers (Re) were 22, 44, and 89, and the initial dimensionless shear rate (S*) varied from 2 to 16. We found (similarly to Rogers (1986) for unstratified flows) the final value of S* at high Re to be [similar] 11, independent of initial S*. The final S* varies at low Re, in agreement with Jacobitz et al. (1997). At low Re, the stationary Richardson number (Ris) depends on both Re and S*, but at higher Re, it varies only with Re. A scaling based on the …
Diapycnal Diffusivity Inferred From Scalar Microstructure Measurements Near The New England Shelf/Slope Front, Chris R. Rehmann, Timothy F. Duda
Diapycnal Diffusivity Inferred From Scalar Microstructure Measurements Near The New England Shelf/Slope Front, Chris R. Rehmann, Timothy F. Duda
Chris R. Rehmann
Conductivity microstructure was used to estimate the diapycnal thermal eddy diffusivity KT near the New England shelf/slope front in early August 1997. Two datasets were collected with a towed vehicle. One involved several horizontal tows in and above a warm, salty layer near the seafloor, and the other was from a tow-yo transect that sampled most of the water column. In the bottom layer, KT derived from microstructure is a factor of about 5 smaller than estimates derived from tracer dispersion at the same density level, and the diffusivity decreases sharply as the buoyancy frequency N increases: KT N−3.1. With …
Emergency Response Canadian Pacific Railway Canadian Main Line, Barry A. Palynchuk Phd, Michael J. Loehr, Robert W. Badger, Robert P. Conroy, Clive H. Mackay
Emergency Response Canadian Pacific Railway Canadian Main Line, Barry A. Palynchuk Phd, Michael J. Loehr, Robert W. Badger, Robert P. Conroy, Clive H. Mackay
Barry A. Palynchuk PhD
In late June 1998, a major storm event occurred in the Adirondack Mountains in the vicinity of Keeseville, New York about 150 miles north of Albany. This storm resulted in unprecedented damage to the Canadian Pacific Railway (CPR) Canadian Mainline along the shores of Lake Champlain. The storm caused 14 major embankment failures and washouts, numerous minor failures, severe bridge foundation scour and a major mainline derailment.
Sediment Control At Water Intakes Along Sand Bed Rivers, Fred L. Ogden
Sediment Control At Water Intakes Along Sand Bed Rivers, Fred L. Ogden
Fred L. Ogden
Results from five physical hydraulic model studies of riverside water intakes situated along the Missouri River reach between Sioux City, Iowa, and St. Louis, Missouri, are presented. Movable-bed, undistorted Froude-scale models are used to determine the effectiveness of structural modifications in the vicinity of the intake to limit the influx of bed-load sediments. Solutions developed in each case include a series of submerged flow-turning vanes located on the riverward side of the intake. A sediment-barrier wall between the vanes and intake ...
Setting Time Effects On Bentonite Water-Well Annulus Seals, Fred L. Ogden
Setting Time Effects On Bentonite Water-Well Annulus Seals, Fred L. Ogden
Fred L. Ogden
Shear strength tests are conducted in a model of a water well on four, commercially available, granular bentonite well sealing products. The time dependency of annulus seal shear strength and resistance to piping is examined. Dry bentonite samples are placed through water in the annular space between the casing and borehole and allowed to set for a specified time. Pressure is applied at a constant rate to one end of the clay seal until shear or piping failure occurs. Pressure and seal displacement data are recorded on a digital data acquisition system. Annulus seal strength and resistance to piping increase …