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1

A Quasi-Three-Dimensional Variably Saturated Groundwater Flow Model for Climate Modeling  

Science Conference Proceedings (OSTI)

In this study, a quasi-three-dimensional, variably saturated groundwater flow model was developed by approximately dividing the three-dimensional soil water and groundwater flow into an unsaturated vertical soil water flow and a horizontal ...

Zhenghui Xie; Zhenhua Di; Zhendong Luo; Qian Ma

2012-02-01T23:59:59.000Z

2

A Guide for Using the Transient Ground-Water Flow Model of the Death Valley Regional Ground-Water Flow System, Nevada and California  

SciTech Connect

This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.

Joan B. Blainey; Claudia C. Faunt, and Mary C. Hill

2006-05-16T23:59:59.000Z

3

Flow Model Development for the Idaho National Laboratory OU 10-08 Sitewide Groundwater Model  

SciTech Connect

A two-dimensional (2D), steady-state groundwater flow model was developed for the Idaho National Laboratory (INL) sitewide groundwater model. A total of 224 wells inside the model domain were used to calibrate the 2D flow model. Three different calibration techniques, zonation approach, pilot point approach and coupled zonation/pilot point approach, were explored and applied during the model development. The pilot point approach allows modelers to model aquifer heterogeneities at various scales, and extract the maximum amount of data from available monitoring data, permitting the best possible representation of flow and transport at the INL.

Hai Huang; Swen Magnuson; Thomas Wood

2005-09-01T23:59:59.000Z

4

The groundwater modeling tool for GRASS (GMTG): Open source groundwater flow modeling  

Science Conference Proceedings (OSTI)

Geographic Information Systems (GIS) are used to store, manipulate and visualize both spatial and non-spatial data. Because of their data manipulating capabilities, GIS have been linked to different simulation models in different research areas and are ... Keywords: GRASS, Geographic Information Systems, Groundwater modeling, MODFLOW

J. J. Carrera-Hernández; S. J. Gaskin

2006-04-01T23:59:59.000Z

5

Three-dimensional model for multi-component reactive transport with variable density groundwater flow  

Science Conference Proceedings (OSTI)

PHWAT is a new model that couples a geochemical reaction model (PHREEQC-2) with a density-dependent groundwater flow and solute transport model (SEAWAT) using the split-operator approach. PHWAT was developed to simulate multi-component reactive transport ... Keywords: Cation exchange, Coastal groundwater flow and chemical transport/reaction, Density-dependent flow, MODFLOW, MT3DMS, PHREEQC-2, PHWAT, SEAWAT, Seawater intrusion, Snow-plough effect

X. Mao; H. Prommer; D. A. Barry; C. D. Langevin; B. Panteleit; L. Li

2006-05-01T23:59:59.000Z

6

Evaluation of uncertainties due to hydrogeological modeling and groundwater flow analysis: Steady flow, transient flow, and thermal studies  

SciTech Connect

Starting with regional geographic, geologic, surface and subsurface hydrologic, and geophysical data for the Tono area in Gifu, Japan, we develop an effective continuum model to simulate subsurface flow and transport in a 4 km by 6 km by 3 km thick fractured granite rock mass overlain by sedimentary layers. Individual fractures are not modeled explicitly. Rather, continuum permeability and porosity distributions are assigned stochastically, based on well-test data and fracture density measurements. Lithologic layering and one major fault, the Tsukiyoshi Fault, are assigned deterministically. We conduct three different studies: (1) the so-called base case, in which the model simulates the steady-state groundwater flow through the site, and then stream trace analysis is used to calculate travel times to the model boundary from specified release points; (2) simulations of transient flow during long term pump tests (LTPT) using the base-case model; and (3) thermal studies in which coupled heat flow and fluid flow are modeled, to examine the effects of the geothermal gradient on groundwater flow. The base-case study indicates that the choice of open or closed lateral boundaries has a strong influence on the regional groundwater flow patterns produced by the models, but no field data exist that can be used to determine which boundary conditions are more realistic. The LTPT study cannot be used to distinguish between the alternative boundary conditions, because the pumping rate is too small to produce an analyzable pressure response at the model boundaries. In contrast, the thermal study shows that the temperature distributions produced by the open and closed models differ greatly. Comparison with borehole temperature data may be used to eliminate the closed model from further consideration.

Doughty, Christine; Karasaki, Kenzi

2002-12-11T23:59:59.000Z

7

A Model For Syn-Eruptive Groundwater Flow During The Phreatoplinian Phase  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » A Model For Syn-Eruptive Groundwater Flow During The Phreatoplinian Phase Of The 28-29 March 1875 Askja Volcano Eruption, Iceland Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Model For Syn-Eruptive Groundwater Flow During The Phreatoplinian Phase Of The 28-29 March 1875 Askja Volcano Eruption, Iceland Details Activities (0) Areas (0) Regions (0) Abstract: We present a groundwater flow model that integrates geological observations, field data, effective permeabilities for fractured lava flows, and historical eyewitness records to explain the change from wet to

8

Coupling geological and numerical models to simulate groundwater flow and contaminant transport in fractured media  

Science Conference Proceedings (OSTI)

A new modeling approach is presented to improve numerical simulations of groundwater flow and contaminant transport in fractured geological media. The approach couples geological and numerical models through an intermediate mesh generation phase. As ... Keywords: Fractures, Geomodel, Influence coefficient technique, Numerical modeling, Tetrahedra

Daniela Blessent; René Therrien; Kerry MacQuarrie

2009-09-01T23:59:59.000Z

9

Using Markov Chain Monte Carlo to quantify parameter uncertainty and its effect on predictions of a groundwater flow model  

Science Conference Proceedings (OSTI)

A statistical Bayesian framework is used to solve the inverse problem and develop the posterior distributions of parameters for a density-driven groundwater flow model. This Bayesian approach is implemented using a Markov Chain Monte Carlo (MCMC) sampling ... Keywords: Conditioning, Groundwater model calibration, Inverse problems, MCMC, Numerical modelling

Ahmed E. Hassan; Hesham M. Bekhit; Jenny B. Chapman

2009-06-01T23:59:59.000Z

10

Uncertainty Analysis Framework - Hanford Site-Wide Groundwater Flow and Transport Model  

Science Conference Proceedings (OSTI)

Pacific Northwest National Laboratory (PNNL) embarked on a new initiative to strengthen the technical defensibility of the predictions being made with a site-wide groundwater flow and transport model at the U.S. Department of Energy Hanford Site in southeastern Washington State. In FY 2000, the focus of the initiative was on the characterization of major uncertainties in the current conceptual model that would affect model predictions. The long-term goals of the initiative are the development and implementation of an uncertainty estimation methodology in future assessments and analyses using the site-wide model. This report focuses on the development and implementation of an uncertainty analysis framework.

Cole, Charles R.; Bergeron, Marcel P.; Murray, Christopher J.; Thorne, Paul D.; Wurstner, Signe K.; Rogers, Phillip M.

2001-11-09T23:59:59.000Z

11

MODELLING OF COUPLED GROUNDWATER FLOW AND RADIONUCLIDE TRANSPORT IN CRYSTALLINE BASEMENT USING FEFLOW 5.0  

E-Print Network (OSTI)

Abstract. The strategy of radioactive waste management of Lithuania provides for evaluating the possibilities of disposal of spent nuclear fuel and long-lived radioactive waste originated from Ignalina NPP in deep geological formations. The initial studies performed in Lithuania during 2001–2004 focused on screening of all potentially prospective geological formations as host formations. Since most information is available on crystalline basement, this formation was selected for the model case studies. Taking into account the assumptions (canister defect scenario proposed by Swedish experts and evaluated by LEI experts), groundwater flow and radionuclide (iodine-129 as mobile and long-lived one) transport modelling using computer code FEFLOW was performed according to geosphere conditions and parameters characteristic of the southern part of Lithuania (0,8×0,6×0,52 km far-field block). The upward groundwater flow through defected canister located in tectonically damaged zone was simulated. The main results of calculations are the following: in the case of upward groundwater flow, the maximum I-129 volumetric activity in single tectonic fracture above defected canister will not exceed 1 Bq/l, and in the active water exchange zone, it is close to 10-2 Bq/l. These figures show that doses obtained by human recipient via aquatic pathway should be below the dose constraint (0,2 mSv/y). More complicated scenarios and assumptions should be investigated in future studies.

Vaidot? Jakimavi?i?t?-maselien?; Jonas Mažeika; Rimantas Petrošius

2006-01-01T23:59:59.000Z

12

A Model For Syn-Eruptive Groundwater Flow During The Phreatoplinian...  

Open Energy Info (EERE)

activity is not obvious because eyewitness records rule out snow, surface water, and heavy rainfall. Hence we use 3D numerical simulations of the syn-eruptive groundwater flow...

13

Monitoring probe for groundwater flow  

DOE Patents (OSTI)

A monitoring probe for detecting groundwater migration. The monitor features a cylinder made of a permeable membrane carrying an array of electrical conductivity sensors on its outer surface. The cylinder is filled with a fluid that has a conductivity different than the groundwater. The probe is placed in the ground at an area of interest to be monitored. The fluid, typically saltwater, diffuses through the permeable membrane into the groundwater. The flow of groundwater passing around the permeable membrane walls of the cylinder carries the conductive fluid in the same general direction and distorts the conductivity field measured by the sensors. The degree of distortion from top to bottom and around the probe is precisely related to the vertical and horizontal flow rates, respectively. The electrical conductivities measured by the sensors about the outer surface of the probe are analyzed to determine the rate and direction of the groundwater flow.

Looney, Brian B. (Aiken, SC); Ballard, Sanford (Albuquerque, NM)

1994-01-01T23:59:59.000Z

14

Modeling Three-Dimensional Groundwater Flow and Advective Contaminant Transport at a Heterogeneous Mountainous Site in Support of Remediation Strategy  

SciTech Connect

A calibrated groundwater flow model for a contaminated site can provide substantial information for assessing and improving hydraulic measures implemented for remediation. A three-dimensional transient groundwater flow model was developed for a contaminated mountainous site, at which interim corrective measures were initiated to limit further spreading of contaminants. This flow model accounts for complex geologic units that vary considerably in thickness, slope, and hydrogeologic properties, as well as large seasonal fluctuations of the groundwater table and flow rates. Other significant factors are local recharge from leaking underground storm drains and recharge from steep uphill areas. The zonation method was employed to account for the clustering of high and low hydraulic conductivities measured in a geologic unit. A composite model was used to represent the bulk effect of thin layers of relatively high hydraulic conductivity found within bedrock of otherwise low conductivity. The inverse simulator ITOUGH2 was used to calibrate the model for the distribution of rock properties. The model was initially calibrated using data collected between 1994 and 1996. To check the validity of the model, it was subsequently applied to predicting groundwater level fluctuation and groundwater flux between 1996 and 1998. Comparison of simulated and measured data demonstrated that the model is capable of predicting the complex flow reasonably well. Advective transport was approximated using pathways of particles originating from source areas of the plumes. The advective transport approximation was in good agreement with the trend of contaminant plumes observed over the years. The validated model was then refined to focus on a subsection of the large system. The refined model was subsequently used to assess the efficiency of hydraulic measures implemented for remediation.

Zhou, Quanlin; Birkholzer, Jens T.; Javandel, Iraj; Jordan, Preston D.

2004-01-14T23:59:59.000Z

15

Numerical Simulation of Inter-basin Groundwater Flow into Northern Yucca Flat, Nevada National Security Site, Using the Death Valley Regional Flow System Model  

SciTech Connect

Models of groundwater flow for the Yucca Flat area of the Nevada National Security Site (NNSS) are under development by the U.S. Department of Energy (DOE) for corrective action investigations of the Yucca Flat-Climax Mine Corrective Action Unit (CAU). One important aspect of these models is the quantity of inter-basin groundwater flow from regional systems to the north. This component of flow, together with its uncertainty, must be properly accounted for in the CAU flow models to provide a defensible regional framework for calculations of radionuclide transport that will support determinations of the Yucca Flat-Climax Mine contaminant boundary. Because characterizing flow boundary conditions in northern Yucca Flat requires evaluation to a higher level of detail than the scale of the Yucca Flat-Climax Mine CAU model can efficiently provide, a study more focused on this aspect of the model was required.

Pohlmann Karl,Ye Ming

2012-03-01T23:59:59.000Z

16

Coupled modeling of groundwater flow solute transport, chemical reactions and microbial processes in the 'SP' island  

Science Conference Proceedings (OSTI)

The Redox Zone Experiment was carried out at the Aespoe HRL in order to study the redox behavior and the hydrochemistry of an isolated vertical fracture zone disturbed by the excavation of an access tunnel. Overall results and interpretation of the Redox Zone Project were reported by /Banwart et al, 1995/. Later, /Banwart et al, 1999/ presented a summary of the hydrochemistry of the Redox Zone Experiment. Coupled groundwater flow and reactive transport models of this experiment were carried out by /Molinero, 2000/ who proposed a revised conceptual model for the hydrogeology of the Redox Zone Experiment which could explain simultaneously measured drawdown and salinity data. The numerical model was found useful to understand the natural system. Several conclusions were drawn about the redox conditions of recharge waters, cation exchange capacity of the fracture zone and the role of mineral phases such as pyrite, calcite, hematite and goethite. This model could reproduce the measured trends of dissolved species, except for bicarbonate and sulfate which are affected by microbially-mediated processes. In order to explore the role of microbial processes, a coupled numerical model has been constructed which accounts for water flow, reactive transport and microbial processes. The results of this model is presented in this report. This model accounts for groundwater flow and reactive transport in a manner similar to that of /Molinero, 2000/ and extends the preliminary microbial model of /Zhang, 2001/ by accounting for microbially-driven organic matter fermentation and organic matter oxidation. This updated microbial model considers simultaneously the fermentation of particulate organic matter by yeast and the oxidation of dissolved organic matter, a product of fermentation. Dissolved organic matter is produced by yeast and serves also as a substrate for iron-reducing bacteria. Model results reproduce the observed increase in bicarbonate and sulfate concentration, thus adding additional evidence for the possibility of organic matter oxidation as the main source of bicarbonate. Model results indicate that pH and Eh are relatively stable. The dissolution-precipitation trends of hematite, pyrite and calcite also coincide with those indicated by the conceptual model. A thorough sensitivity analysis has been performed for the most relevant microbial parameters as well as for initial and boundary POC and DOC concentrations. The results of such analysis indicate that computed concentrations of bicarbonate, sulfate and DOC are sensitive to most of the microbial parameters, including specific growth rates, half-saturation constants, proportionality coefficients and yield coefficients. Model results, however, are less sensitive to the yield coefficient of DOC to iron-reducer bacteria. The sensitivity analysis indicates that changes in fermentation microbial parameters affect the growth of the iron-reducer, thus confirming the interconnection of both microbial processes. Computed concentrations of bicarbonate and sulfate are found to be sensitive to changes in the initial concentration of POC and the boundary concentration of DOC, but they lack sensitivity to the initial concentration of DOC and the boundary concentration of POC. The explanation for such result is related to the fact that POC has a low mobility due to its large molecular weight. DOC, however, can migrate downwards. Although a coupled hydro-bio-geochemical 1-D model can reproduce the observed ''unexpected'' increase of concentrations of bicarbonate and sulfate at a depth of 70 m, further modeling work is required in order to obtain a similar conclusion under the more realistic two dimensional conditions of the fracture zone.

Samper, Javier; Molinero, Jorg; Changbing, Yang; Zhang, Guoxiang

2003-12-01T23:59:59.000Z

17

Regional groundwater flow and tritium transport modeling and risk assessment of the underground test area, Nevada Test Site, Nevada  

Science Conference Proceedings (OSTI)

The groundwater flow system of the Nevada Test Site and surrounding region was evaluated to estimate the highest potential current and near-term risk to the public and the environment from groundwater contamination downgradient of the underground nuclear testing areas. The highest, or greatest, potential risk is estimated by assuming that several unusually rapid transport pathways as well as public and environmental exposures all occur simultaneously. These conservative assumptions may cause risks to be significantly overestimated. However, such a deliberate, conservative approach ensures that public health and environmental risks are not underestimated and allows prioritization of future work to minimize potential risks. Historical underground nuclear testing activities, particularly detonations near or below the water table, have contaminated groundwater near testing locations with radioactive and nonradioactive constituents. Tritium was selected as the contaminant of primary concern for this phase of the project because it is abundant, highly mobile, and represents the most significant contributor to the potential radiation dose to humans for the short term. It was also assumed that the predicted risk to human health and the environment from tritium exposure would reasonably represent the risk from other, less mobile radionuclides within the same time frame. Other contaminants will be investigated at a later date. Existing and newly collected hydrogeologic data were compiled for a large area of southern Nevada and California, encompassing the Nevada Test Site regional groundwater flow system. These data were used to develop numerical groundwater flow and tritium transport models for use in the prediction of tritium concentrations at hypothetical human and ecological receptor locations for a 200-year time frame. A numerical, steady-state regional groundwater flow model was developed to serve as the basis for the prediction of the movement of tritium from the underground testing areas on a regional scale. The groundwater flow model was used in conjunction with a particle-tracking code to define the pathlines followed by groundwater particles originating from 415 points associated with 253 nuclear test locations. Three of the most rapid pathlines were selected for transport simulations. These pathlines are associated with three nuclear test locations, each representing one of the three largest testing areas. These testing locations are: BOURBON on Yucca Flat, HOUSTON on Central Pahute Mesa, and TYBO on Western Pahute Mesa. One-dimensional stochastic tritium transport simulations were performed for the three pathlines using the Monte Carlo method with Latin hypercube sampling. For the BOURBON and TYBO pathlines, sources of tritium from other tests located along the same pathline were included in the simulations. Sensitivity analyses were also performed on the transport model to evaluate the uncertainties associated with the geologic model, the rates of groundwater flow, the tritium source, and the transport parameters. Tritium concentration predictions were found to be mostly sensitive to the regional geology in controlling the horizontal and vertical position of transport pathways. The simulated concentrations are also sensitive to matrix diffusion, an important mechanism governing the migration of tritium in fractured carbonate and volcanic rocks. Source term concentration uncertainty is most important near the test locations and decreases in importance as the travel distance increases. The uncertainty on groundwater flow rates is as important as that on matrix diffusion at downgradient locations. The risk assessment was performed to provide conservative and bounding estimates of the potential risks to human health and the environment from tritium in groundwater. Risk models were designed by coupling scenario-specific tritium intake with tritium dose models and cancer and genetic risk estimates using the Monte Carlo method. Estimated radiation doses received by individuals from chronic exposure to tritium, and the corre

None

1997-10-01T23:59:59.000Z

18

A groundwater flow and transport model of long-term radionuclide migration in central Frenchman flat, Nevada test site  

Science Conference Proceedings (OSTI)

A set of groundwater flow and transport models were created for the Central Testing Area of Frenchman Flat at the former Nevada Test Site to investigate the long-term consequences of a radionuclide migration experiment that was done between 1975 and 1990. In this experiment, radionuclide migration was induced from a small nuclear test conducted below the water table by pumping a well 91 m away. After radionuclides arrived at the pumping well, the contaminated effluent was discharged to an unlined ditch leading to a playa where it was expected to evaporate. However, recent data from a well near the ditch and results from detailed models of the experiment by LLNL personnel have convincingly demonstrated that radionuclides from the ditch eventually reached the water table some 220 m below land surface. The models presented in this paper combine aspects of these detailed models with concepts of basin-scale flow to estimate the likely extent of contamination resulting from this experiment over the next 1,000 years. The models demonstrate that because regulatory limits for radionuclide concentrations are exceeded only by tritium and the half-life of tritium is relatively short (12.3 years), the maximum extent of contaminated groundwater has or will soon be reached, after which time the contaminated plume will begin to shrink because of radioactive decay. The models also show that past and future groundwater pumping from water supply wells within Frenchman Flat basin will have negligible effects on the extent of the plume.

Kwicklis, Edward Michael [Los Alamos National Laboratory; Becker, Naomi M [Los Alamos National Laboratory; Ruskauff, Gregory [NAVARRO-INTERA, LLC.; De Novio, Nicole [GOLDER AND ASSOC.; Wilborn, Bill [US DOE NNSA NSO

2010-11-10T23:59:59.000Z

19

TYBO/BENHAM: Model Analysis of Groundwater Flow and Radionuclide Migration from Underground Nuclear Tests in Southwestern Pahute Mesa, Nevada  

Science Conference Proceedings (OSTI)

Recent field studies have led to the discovery of trace quantities of plutonium originating from the BENHAM underground nuclear test in two groundwater observation wells on Pahute Mesa at the Nevada Test Site. These observation wells are located 1.3 km from the BENHAM underground nuclear test and approximately 300 m from the TYBO underground nuclear test. In addition to plutonium, several other conservative (e.g. tritium) and reactive (e.g. cesium) radionuclides were found in both observation wells. The highest radionuclide concentrations were found in a well sampling a welded tuff aquifer more than 500m above the BENHAM emplacement depth. These measurements have prompted additional investigations to ascertain the mechanisms, processes, and conditions affecting subsurface radionuclide transport in Pahute Mesa groundwater. This report describes an integrated modeling approach used to simulate groundwater flow, radionuclide source release, and radionuclide transport near the BENHAM and TYBO underground nuclear tests on Pahute Mesa. The components of the model include a flow model at a scale large enough to encompass many wells for calibration, a source-term model capable of predicting radionuclide releases to aquifers following complex processes associated with nonisothermal flow and glass dissolution, and site-scale transport models that consider migration of solutes and colloids in fractured volcanic rock. Although multiple modeling components contribute to the methodology presented in this report, they are coupled and yield results consistent with laboratory and field observations. Additionally, sensitivity analyses are conducted to provide insight into the relative importance of uncertainty ranges in the transport parameters.

Andrew Wolfsberg; Lee Glascoe; Guoping Lu; Alyssa Olson; Peter Lichtner; Maureen McGraw; Terry Cherry; Guy Roemer

2002-09-01T23:59:59.000Z

20

Modeling of Groundwater Flow and Radionuclide Transport at the Climax Mine sub-CAU, Nevada Test Site  

SciTech Connect

The Yucca Flat-Climax Mine Corrective Action Unit (CAU) on the Nevada Test Site comprises 747 underground nuclear detonations, all but three of which were conducted in alluvial, volcanic, and carbonate rocks in Yucca Flat. The remaining three tests were conducted in the very different hydrogeologic setting of the Climax Mine granite stock located in Area 15 at the northern end of Yucca Flat. As part of the Corrective Action Investigation (CAI) for the Yucca Flat-Climax Mine CAU, models of groundwater flow and radionuclide transport will be developed for Yucca Flat. However, two aspects of these CAU-scale models require focused modeling at the northern end of Yucca Flat beyond the capability of these large models. First, boundary conditions and boundary flows along the northern reaches of the Yucca Flat-Climax Mine CAU require evaluation to a higher level of detail than the CAU-scale Yucca Flat model can efficiently provide. Second, radionuclide fluxes from the Climax tests require analysis of flow and transport in fractured granite, a unique hydrologic environment as compared to Yucca Flat proper. This report describes the Climax Mine sub-CAU modeling studies conducted to address these issues, with the results providing a direct feed into the CAI for the Yucca Flat-Climax Mine CAU. Three underground nuclear detonations were conducted for weapons effects testing in the Climax stock between 1962 and 1966: Hard Hat, Pile Driver, and Tiny Tot. Though there is uncertainty regarding the position of the water table in the stock, it is likely that all three tests were conducted in the unsaturated zone. In the early 1980s, the Spent Fuel Test-Climax (SFT-C) was constructed to evaluate the feasibility of retrievable, deep geologic storage of commercial nuclear reactor wastes. Detailed mapping of fractures and faults carried out for the SFT-C studies greatly expanded earlier data sets collected in association with the nuclear tests and provided invaluable information for subsequent modeling studies at Climax. The objectives of the Climax Mine sub-CAU work are to (1) provide simulated heads and groundwater flows for the northern boundaries of the Yucca Flat-Climax Mine CAU model, while incorporating alternative conceptualizations of the hydrogeologic system with their associated uncertainty, and (2) provide radionuclide fluxes from the three tests in the Climax stock using modeling techniques that account for groundwater flow in fractured granite. Meeting these two objectives required two different model scales. The northern boundary groundwater fluxes were addressed using the Death Valley Regional Flow System (DVRFS) model (Belcher, 2004) developed by the U.S. Geological Survey as a modeling framework, with refined hydrostratigraphy in a zone north of Yucca Flat and including Climax stock. Radionuclide transport was simulated using a separate model confined to the granite stock itself, but linked to regional groundwater flow through boundary conditions and calibration targets.

K. Pohlmann; M. Ye; D. Reeves; M. Zavarin; D. Decker; J. Chapman

2007-09-28T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Groundwater Model Validation  

SciTech Connect

Models have an inherent uncertainty. The difficulty in fully characterizing the subsurface environment makes uncertainty an integral component of groundwater flow and transport models, which dictates the need for continuous monitoring and improvement. Building and sustaining confidence in closure decisions and monitoring networks based on models of subsurface conditions require developing confidence in the models through an iterative process. The definition of model validation is postulated as a confidence building and long-term iterative process (Hassan, 2004a). Model validation should be viewed as a process not an end result. Following Hassan (2004b), an approach is proposed for the validation process of stochastic groundwater models. The approach is briefly summarized herein and detailed analyses of acceptance criteria for stochastic realizations and of using validation data to reduce input parameter uncertainty are presented and applied to two case studies. During the validation process for stochastic models, a question arises as to the sufficiency of the number of acceptable model realizations (in terms of conformity with validation data). Using a hierarchical approach to make this determination is proposed. This approach is based on computing five measures or metrics and following a decision tree to determine if a sufficient number of realizations attain satisfactory scores regarding how they represent the field data used for calibration (old) and used for validation (new). The first two of these measures are applied to hypothetical scenarios using the first case study and assuming field data consistent with the model or significantly different from the model results. In both cases it is shown how the two measures would lead to the appropriate decision about the model performance. Standard statistical tests are used to evaluate these measures with the results indicating they are appropriate measures for evaluating model realizations. The use of validation data to constrain model input parameters is shown for the second case study using a Bayesian approach known as Markov Chain Monte Carlo. The approach shows a great potential to be helpful in the validation process and in incorporating prior knowledge with new field data to derive posterior distributions for both model input and output.

Ahmed E. Hassan

2006-01-24T23:59:59.000Z

22

Phase II Groundwater Flow Model of Corrective Action Unit 98: Frenchman Flat, Nevada Test Site, Nye County, Nevada, Rev. No.: 0  

SciTech Connect

The Phase II Frenchman Flat groundwater flow model is a key element in the ''Federal Facility Agreement and Consent Order'' (FFACO) (1996) corrective action strategy for the Underground Test Area (UGTA) Frenchman Flat corrective action unit (CAU). The objective of this integrated process is to provide an estimate of the vertical and horizontal extent of contaminant migration for each CAU to predict contaminant boundaries. A contaminant boundary is the model-predicted perimeter that defines the extent of radionuclide-contaminated groundwater from underground testing above background conditions exceeding the ''Safe Drinking Water Act'' (SDWA) standards. The contaminant boundary will be composed of both a perimeter boundary and a lower hydrostratigraphic unit (HSU) boundary. The computer model will predict the location of this boundary within 1,000 years and must do so at a 95 percent level of confidence. Additional results showing contaminant concentrations and the location of the contaminant boundary at selected times will also be presented. These times may include the verification period, the end of the five-year proof-of-concept period, as well as other times that are of specific interest. This report documents the development and implementation of the groundwater flow model for the Frenchman Flat CAU. Specific objectives of the Phase II Frenchman Flat flow model are to: (1) Incorporate pertinent information and lessons learned from the Phase I Frenchman Flat CAU models. (2) Develop a three-dimensional (3-D), mathematical flow model that incorporates the important physical features of the flow system and honors CAU-specific data and information. (3) Simulate the steady-state groundwater flow system to determine the direction and magnitude of groundwater fluxes based on calibration to Frenchman Flat hydrogeologic data. (4) Quantify the uncertainty in the direction and magnitude of groundwater flow due to uncertainty in parameter values and alternative component conceptual models (e.g., geology, boundary flux, and recharge).

John McCord

2006-05-01T23:59:59.000Z

23

Accounting for surface-groundwater interactions and their uncertainty in river and groundwater models: A case study in the Namoi River, Australia  

Science Conference Proceedings (OSTI)

Surface-groundwater (SW-GW) interactions constitute a critical proportion of the surface and groundwater balance especially during dry conditions. Conjunctive management of surface and groundwater requires an explicit account of the exchange flux between ... Keywords: Groundwater model, Groundwater pumping, Nonstationarity of low flows, River low flow, River model, Surface-groundwater interaction, Uncertainty analysis, eWater Source

David W. Rassam, Luk Peeters, Trevor Pickett, Ian Jolly, Linda Holz

2013-12-01T23:59:59.000Z

24

Phase II Hydrologic Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 98: Frenchman Flat, Nye County, Nevada, Rev. No.: 0  

SciTech Connect

This report documents pertinent hydrologic data and data analyses as part of the Phase II Corrective Action Investigation (CAI) for Frenchman Flat (FF) Corrective Action Unit (CAU): CAU 98. The purpose of this data compilation and related analyses is to provide the primary reference to support the development of the Phase II FF CAU groundwater flow model.

John McCord

2004-12-01T23:59:59.000Z

25

Validation Analysis of the Groundwater Flow and Transport Model of the Central Nevada Test Area  

Science Conference Proceedings (OSTI)

The Central Nevada Test Area (CNTA) is a U.S. Department of Energy (DOE) site undergoing environmental restoration. The CNTA is located about 95 km northeast of Tonopah, Nevada, and 175 km southwest of Ely, Nevada (Figure 1.1). It was the site of the Faultless underground nuclear test conducted by the U.S. Atomic Energy Commission (DOE's predecessor agency) in January 1968. The purposes of this test were to gauge the seismic effects of a relatively large, high-yield detonation completed in Hot Creek Valley (outside the Nevada Test Site [NTS]) and to determine the suitability of the site for future large detonations. The yield of the Faultless underground nuclear test was between 200 kilotons and 1 megaton (DOE, 2000). A three-dimensional flow and transport model was created for the CNTA site (Pohlmann et al., 1999) and determined acceptable by DOE and the Nevada Division of Environmental Protection (NDEP) for predicting contaminant boundaries for the site.

A. Hassan; J. Chapman; H. Bekhit; B. Lyles; K. Pohlmann

2006-09-30T23:59:59.000Z

26

Groundwater modeling: Application of a multiphase fluid flow model as a decision-making tool for assessing and remediating installation restoration program sites. Master's thesis  

Science Conference Proceedings (OSTI)

This research examined a two-dimensional numerical model, VALOR, which can simulate multiphase fluid flow in soils and groundwater, and evaluated the applicability of the model as a decision-making tool for assessing and remediating IRP sites. Model sensitivity analyses were conducted to study the influence of grid sizes, soil types, and organic release rates on the simulated migration of both light and dense non-aqueous phase liquids (NAPLs). The VALOR model was applied to a case study of a JP-4 release at Wright-Patterson AFB, Ohio. The finer grid sizes provide the most accurate definition of NAPL distribution. The soil type and release rate sensitivity analyses demonstrate that NAPL migrates quicker through coarse sands than fine sand and clay. The light NAPL ponds at the water table and spreads laterally. The dense NAPL migrates through the subsurface and ponds at the aquifer bottom. The fast organic release simulations predict wider vertical pathways of migration. The slow organic release simulations predict higher light NAPL saturation at the water table. The case study indicates that within limits, VALOR may be useful for assessing NAPL distribution, estimating contaminated soil volumes, and evaluating remediation alternatives.... Groundwater modeling, Non-aqueous Phase Liquids: NAPL, Multiphase fluid flow model, Installation Restoration Program, IRP.

Scott, D.J.

1993-09-01T23:59:59.000Z

27

Comparison of Two Groundwater Flow Models--UNSAT1D and HELP  

Science Conference Proceedings (OSTI)

Utilities seeking to predict leakage from capped solid-waste disposal sites must select models that closely represent the landfill design and meteorology of the site. Predictions made by two models for three sites under varied conditions gave similar results for humid conditions. However, the predictions of HELP, the simpler model, were less useful for semihumid and arid environments.

1984-10-01T23:59:59.000Z

28

Modeling the reactive inorganic solute distributions in the groundwater flow systems of the Hanford Site using inverse analytical modeling techniques  

E-Print Network (OSTI)

Inverse analytical techniques were used to model solute distributions and determine transport parameters for two flow systems in the Yakima Basalt subgroup at the Hanford Site in Washington state. Previous studies of these flow systems used chloride as a tracer to determine the transverse dispersivities of several of the Hanford flow systems. This study analyzes three reactive solute distributions, two of which are coincident, to determine aquifer and solute reactions parameters. In addition to modeling the transport of two solutes, a chemical speciation model, MINTEQA2, was used to determine saturation indices for the sample waters in an effort to verify observed secondary mineralization. Boron and potassium were the two solute distributions modeled in this study. The analytical model results accurately reproduce the observed field conditions, comply with the assumptions of the conceptual model, and match the results of the previous chloride study. The parameters determined by the analytical model include the source size and dimension, transverse dispersivity, and reaction rate/solute velocity ratio. The reaction rate term is used to describe the first order reactions experienced by boron and potassium. This term is believed to represent the affect of both precipitation and non-equilibrium sorption reactions. Due to the nature of the problem, this ratio cannot be separated for its individual terms. However, the relative rates of reaction for the solutes are determined.

Adamski, Mark Robert

1993-01-01T23:59:59.000Z

29

Modeling and assessment of flow and transport in the Hueco Bolson, a transboundary groundwater system: the El Paso / Cuidad Juarez case  

E-Print Network (OSTI)

Potential contamination from hazardous and solid waste landfills stemming from population increase, rapid industrialization, and the proliferation of assembly plants known as the maquiladoras, are of major concern in the U.S.-Mexican border area. Additionally, historical, current, and future stresses on the Hueco Bolson alluvial aquifer in the El Paso/Ciudad Juarez area due to excessive groundwater withdrawal can affect contaminant migration in the area. In the current study, an updated and improved threedimensional numerical groundwater flow and transport model is developed using a current Hueco Bolson groundwater availability model as its basis. The model with contaminant transport is required to access and characterize the extent of vulnerability of the aquifer to potential contamination from landfills in the El Paso/Ciudad Juarez border area. The model developed in this study is very capable of serving as the basis of future studies for water availability, water quality, and contamination assessments in the Hueco Bolson. The implementation of fate and transport modeling and the incorporation of the Visual MODFLOW® pre and post processor, requiring MODFLOW 2000 data conversion, enabled significant enhancements to the numerical modeling and computing capabilities for the Hueco Bolson. The model in the current research was also developed by employing MT3DMS©, ZONEBUDGET, and Visual PEST® for automated calibrations. Simulation results found that the Hueco Bolson released more water from storage than the aquifer was being recharged in response to increased pumping to supply the growing border area population. Hence, significant head drops and high levels of drawdown were observed in the El Paso/Ciudad Juarez area. Predictive simulations were completed representing scenarios of potential contamination from the border area sites. Fate and transport results were most sensitive to hydraulic conductivities, flow velocities, and directions at the sites. Sites that were located within the vicinity of the El Paso Valley and the Rio Grande River, where head differences and permeabilities were significant, exhibited the highest potentials for contaminant migration.

Nwaneshiudu, Okechukwu

2007-12-01T23:59:59.000Z

30

Geochemical and Isotopic Interpretations of Groundwater Flow in the Oasis Valley Flow System, Southern Nevada  

SciTech Connect

This report summarizes the findings of a geochemical investigation of the Pahute Mesa-Oasis Valley groundwater flow system in southwestern Nevada. It is intended to provide geochemical data and interpretations in support of flow and contaminant transport modeling for the Western and Central Pahute Mesa Corrective Action Units.

J.M. Thomas; F.C. Benedict, Jr.; T.P. Rose; R.L. Hershey; J.B. Paces; Z.E. Peterman; I.M. Farnham; K.H. Johannesson; A.K. Singh; K.J. Stetzenbach; G.B. Hudson; J.M. Kenneally; G.F. Eaton; D.K. Smith

2003-01-08T23:59:59.000Z

31

A Hydrostrat Model and Alternatives for Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 99: Rainer Mesa-Shoshone Mountain, Nye County, Nevada  

Science Conference Proceedings (OSTI)

The three-dimensional hydrostratigraphic framework model for the Rainier Mesa-Shoshone Mountain Corrective Action Unit was completed in Fiscal Year 2006. The model extends from eastern Pahute Mesa in the north to Mid Valley in the south and centers on the former nuclear testing areas at Rainier Mesa, Aqueduct Mesa, and Shoshone Mountain. The model area also includes an overlap with the existing Underground Test Area Corrective Action Unit models for Yucca Flat and Pahute Mesa. The model area is geologically diverse and includes un-extended yet highly deformed Paleozoic terrain and high volcanic mesas between the Yucca Flat extensional basin on the east and caldera complexes of the Southwestern Nevada Volcanic Field on the west. The area also includes a hydrologic divide between two groundwater sub-basins of the Death Valley regional flow system. A diverse set of geological and geophysical data collected over the past 50 years was used to develop a structural model and hydrostratigraphic system for the model area. Three deep characterization wells, a magnetotelluric survey, and reprocessed gravity data were acquired specifically for this modeling initiative. These data and associated interpretive products were integrated using EarthVision{reg_sign} software to develop the three-dimensional hydrostratigraphic framework model. Crucial steps in the model building process included establishing a fault model, developing a hydrostratigraphic scheme, compiling a drill-hole database, and constructing detailed geologic and hydrostratigraphic cross sections and subsurface maps. The more than 100 stratigraphic units in the model area were grouped into 43 hydrostratigraphic units based on each unit's propensity toward aquifer or aquitard characteristics. The authors organized the volcanic units in the model area into 35 hydrostratigraphic units that include 16 aquifers, 12 confining units, 2 composite units (a mixture of aquifer and confining units), and 5 intrusive confining units. The underlying pre-Tertiary rocks are divided into six hydrostratigraphic units, including three aquifers and three confining units. Other units include an alluvial aquifer and a Mesozoic-age granitic confining unit. The model depicts the thickness, extent, and geometric relationships of these hydrostratigraphic units ('layers' in the model). The model also incorporates 56 Tertiary normal faults and 4 Mesozoic thrust faults. The complexity of the model area and the non-uniqueness of some of the interpretations incorporated into the base model made it necessary to formulate alternative interpretations for some of the major features in the model. Four of these alternatives were developed so they can be modeled in the same fashion as the base model. This work was done for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office in support of the Underground Test Area Subproject of the Environmental Restoration Project.

NSTec Geotechnical Sciences Group

2007-03-01T23:59:59.000Z

32

Modeling the effects of atmospheric emissions on groundwater composition  

SciTech Connect

A composite model of atmospheric, unsaturated and groundwater transport is developed to evaluate the processes determining the distribution of atmospherically derived contaminants in groundwater systems and to test the sensitivity of simulated contaminant concentrations to input parameters and model linkages. One application is to screen specific atmospheric emissions for their potential in determining groundwater age. Temporal changes in atmospheric emissions could provide a recognizable pattern in the groundwater system. The model also provides a way for quantifying the significance of uncertainties in the tracer source term and transport parameters on the contaminant distribution in the groundwater system, an essential step in using the distribution of contaminants from local, point source atmospheric emissions to examine conceptual models of groundwater flow and transport.

Brown, T.J.

1994-12-31T23:59:59.000Z

33

A Hydrostratigraphic System for Modeling Groundwater Flow and Radionuclide Migration at the Corrective Action Unit Scale, Nevada Test Site and Surrounding Areas, Clark, Lincoln, and Nye Counties, Nevada  

SciTech Connect

Underground Test Area (UGTA) corrective action unit (CAU) groundwater flow and contaminant transport models of the Nevada Test Site (NTS) and vicinity are built upon hydrostratigraphic framework models (HFMs) that utilize the hydrostratigraphic unit (HSU) as the fundamental modeling component. The delineation and three-dimensional (3-D) modeling of HSUs within the highly complex geologic terrain that is the NTS requires a hydrostratigraphic system that is internally consistent, yet flexible enough to account for overlapping model areas, varied geologic terrain, and the development of multiple alternative HFMs. The UGTA CAU-scale hydrostratigraphic system builds on more than 50 years of geologic and hydrologic work in the NTS region. It includes 76 HSUs developed from nearly 300 stratigraphic units that span more than 570 million years of geologic time, and includes rock units as diverse as marine carbonate and siliciclastic rocks, granitic intrusives, rhyolitic lavas and ash-flow tuffs, and alluvial valley-fill deposits. The UGTA CAU-scale hydrostratigraphic system uses a geology-based approach and two-level classification scheme. The first, or lowest, level of the hydrostratigraphic system is the hydrogeologic unit (HGU). Rocks in a model area are first classified as one of ten HGUs based on the rock’s ability to transmit groundwater (i.e., nature of their porosity and permeability), which at the NTS is mainly a function of the rock’s primary lithology, type and degree of postdepositional alteration, and propensity to fracture. The second, or highest, level within the UGTA CAU-scale hydrostratigraphic system is the HSU, which is the fundamental mapping/modeling unit within UGTA CAU-scale HFMs. HSUs are 3-D bodies that are represented in the finite element mesh for the UGTA groundwater modeling process. HSUs are defined systematically by stratigraphically organizing HGUs of similar character into larger HSUs designations. The careful integration of stratigraphic information in the development of HSUs is important to assure individual HSUs are internally consistent, correlatable, and mappable throughout all the model areas.

Lance Prothro, Sigmund Drellack Jr., Jennifer Mercadante

2009-01-31T23:59:59.000Z

34

Phase I Hydrologic Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 99: Rainier Mesa/Shoshone Mountain, Nevada Test Site, Nye County, Nevada, Revision 1  

Science Conference Proceedings (OSTI)

This document presents a summary and framework of the available hydrologic data and other information directly relevant to the development of the Rainier Mesa/Shoshone Mountain (RMSM) Corrective Action Unit (CAU) 99 groundwater flow models. Where appropriate, data and information documented elsewhere are briefly summarized with reference to the complete documentation.

Nathan Bryant

2008-05-01T23:59:59.000Z

35

Thermally Induced Groundwater Flow Resulting from an Underground Nuclear Test  

SciTech Connect

The authors examine the transient residual thermal signal resulting from an underground nuclear test (buried below the water table) and its potential to affect local groundwater flow and radionuclide migration in a saturated, fractured, volcanic aquifer system. Thermal profiles measured in a drillback hole between 154 days and 6.5 years after the test have been used to calibrate a non-isothermal model of fluid flow. In this process, they have estimated the magnitude and relative changes in permeability, porosity and fracture density between different portions of the disturbed and undisturbed geologic medium surrounding the test location. The relative impacts of buoyancy forces (arising from the thermal residual of the test and the background geothermal gradient) and horizontal pressure gradients on the post-test flow system are better understood. A transient particle/streamline model of contaminant transport is used to visualize streamlines and streaklines of the flow field and to examine the migration of non-reactive radionuclides. Sensitivity analyses are performed to understand the effects of local and sub-regional geologic features, and the effects of fractured zones on the movement of groundwater and thermal energy. Conclusions regarding the overall effect of the thermal regime on the residence times and fluxes of radionuclides out of the system are drawn, and implications for more complicated, reactive contaminant transport are discussed.

Maxwell, R.M.; Tompson, A.F.B.; Rambo, J.T.; Carle, S.F.; Pawloski, G.A.

2000-12-16T23:59:59.000Z

36

Phase I Hydrologic Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nye County, Nevada, Rev. No.: 0  

Science Conference Proceedings (OSTI)

The U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO) initiated the Underground Test Area (UGTA) Project to assess and evaluate the effects of the underground nuclear weapons tests on groundwater beneath the Nevada Test Site (NTS) and vicinity. The framework for this evaluation is provided in Appendix VI, Revision No. 1 (December 7, 2000) of the Federal Facility Agreement and Consent Order (FFACO, 1996). Section 3.0 of Appendix VI ''Corrective Action Strategy'' of the FFACO describes the process that will be used to complete corrective actions specifically for the UGTA Project. The objective of the UGTA corrective action strategy is to define contaminant boundaries for each UGTA corrective action unit (CAU) where groundwater may have become contaminated from the underground nuclear weapons tests. The contaminant boundaries are determined based on modeling of groundwater flow and contaminant transport. A summary of the FFACO corrective action process and the UGTA corrective action strategy is provided in Section 1.5. The FFACO (1996) corrective action process for the Yucca Flat/Climax Mine CAU 97 was initiated with the Corrective Action Investigation Plan (CAIP) (DOE/NV, 2000a). The CAIP included a review of existing data on the CAU and proposed a set of data collection activities to collect additional characterization data. These recommendations were based on a value of information analysis (VOIA) (IT, 1999), which evaluated the value of different possible data collection activities, with respect to reduction in uncertainty of the contaminant boundary, through simplified transport modeling. The Yucca Flat/Climax Mine CAIP identifies a three-step model development process to evaluate the impact of underground nuclear testing on groundwater to determine a contaminant boundary (DOE/NV, 2000a). The three steps are as follows: (1) Data compilation and analysis that provides the necessary modeling data that is completed in two parts: the first addressing the groundwater flow model, and the second the transport model. (2) Development of a groundwater flow model. (3) Development of a groundwater transport model. This report presents the results of the first part of the first step, documenting the data compilation, evaluation, and analysis for the groundwater flow model. The second part, documentation of transport model data will be the subject of a separate report. The purpose of this document is to present the compilation and evaluation of the available hydrologic data and information relevant to the development of the Yucca Flat/Climax Mine CAU groundwater flow model, which is a fundamental tool in the prediction of the extent of contaminant migration. Where appropriate, data and information documented elsewhere are summarized with reference to the complete documentation. The specific task objectives for hydrologic data documentation are as follows: (1) Identify and compile available hydrologic data and supporting information required to develop and validate the groundwater flow model for the Yucca Flat/Climax Mine CAU. (2) Assess the quality of the data and associated documentation, and assign qualifiers to denote levels of quality. (3) Analyze the data to derive expected values or spatial distributions and estimates of the associated uncertainty and variability.

John McCord

2006-06-01T23:59:59.000Z

37

Groundwater flow near the Shoal Site, Sand Springs Range, Nevada: Impact of density-driven flow  

Science Conference Proceedings (OSTI)

The nature of flow from a highland recharge area in a mountain range in north-central Nevada to discharge areas on either side of the range is evaluated to refine a conceptual model of contaminant transport from an underground nuclear test conducted beneath the range. The test, known as the Shoal event, was conducted in 1963 in granitic rocks of the Sand Springs Range. Sparse hydraulic head measurements from the early 1960s suggest flow from the shot location to the east to Fairview Valley, while hydrochemistry supports flow to salt pans in Fourmile Flat to the west. Chemical and isotopic data collected from water samples and during well-logging arc best explained by a reflux brine system on the west side of the Sand Springs Range, rather than a typical local flow system where all flow occurs from recharge areas in the highlands to a central discharge area in a playa. Instead, dense saline water from the playa is apparently being driven toward the range by density contrasts. The data collected between the range and Fourmile Flat suggest the groundwater is a mixture of younger, fresher recharge water with older brine. Chemical contrasts between groundwater in the east and west valleys reflect the absence of re-flux water in Fairview Valley because the regional discharge area is distant and thus there is no accumulation of salts. The refluxing hydraulic system probably developed after the end of the last pluvial period and differences between the location of the groundwater divide based on hydraulic and chemical indicators could reflect movement of the divide as the groundwater system adjusts to the new reflux condition.

Chapman, J.; Mihevc, T.; McKay, A.

1994-09-01T23:59:59.000Z

38

Simulation of groundwater flow at the LBNL site using TOUGH2  

SciTech Connect

In the late 1980s, groundwater contamination was detected at the site of the Lawrence Berkeley National Laboratory (LBNL). A detailed investigation was conducted to locate the source and the extent of the contamination. Interim corrective measures were initiated where appropriate and required, typically directed towards removing the source of contamination, excavating contaminated soil, and limiting further spreading of contaminants. As the first step for predicting the fate of remaining contaminants, a three-dimensional transient groundwater flow model was developed for the complex hydrogeological situation. This flow model captured strong variations in thickness, slope, and hydrogeological properties of geologic units, representative of a mountainous groundwater system with accentuated morphology. The flow model accounts for strong seasonal fluctuations in the groundwater table. Other significant factors are local recharge from leaking underground storm drains and significant water re charge from steep hills located upstream. The strong heterogeneous rock properties were calibrated using the inverse simulator ITOUGH2. For validation purposes, the model was calibrated for a time period from 1994 to 1996, and then applied to a period from 1996 to 1998. Comparison of simulated and measured water levels demonstrated that the model accurately represents the complex flow situation, including the significant seasonal fluctuations in water table and flow rate. Paths of particles originating from contaminant plumes in the simulated transient flow fields were obtained to represent advective transport.

Zhou, Quanlin; Birkholzer, Jens T.; Javandel, Iraj; Jordan, Preston D.

2003-05-12T23:59:59.000Z

39

The Underground Test Area Project of the Nevada Test Site: Building Confidence in Groundwater Flow and Transport Models at Pahute Mesa Through Focused Characterization Studies  

SciTech Connect

Pahute Mesa at the Nevada Test Site contains about 8.0E+07 curies of radioactivity caused by underground nuclear testing. The Underground Test Area Subproject has entered Phase II of data acquisition, analysis, and modeling to determine the risk to receptors from radioactivity in the groundwater, establish a groundwater monitoring network, and provide regulatory closure. Evaluation of radionuclide contamination at Pahute Mesa is particularly difficult due to the complex stratigraphy and structure caused by multiple calderas in the Southwestern Nevada Volcanic Field and overprinting of Basin and Range faulting. Included in overall Phase II goals is the need to reduce the uncertainty and improve confidence in modeling results. New characterization efforts are underway, and results from the first year of a three-year well drilling plan are presented.

Pawloski, G A; Wurtz, J; Drellack, S L

2009-12-29T23:59:59.000Z

40

Investigation of Groundwater Flow in Foothill and Mountain regions using Heat Flow measurements  

E-Print Network (OSTI)

balance with the thermal energy balance. The 3D subsurfacebalance and subsurface thermal energy balance underlies theof model domain for thermal energy and groundwater mass

Fogg, Graham E.; Trask, James C

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Update to the Ground-Water Withdrawals Database for the Death Valley REgional Ground-Water Flow System, Nevada and California, 1913-2003  

SciTech Connect

Ground-water withdrawal estimates from 1913 through 2003 for the Death Valley regional ground-water flow system are compiled in an electronic database to support a regional, three-dimensional, transient ground-water flow model. This database updates a previously published database that compiled estimates of ground-water withdrawals for 1913–1998. The same methodology is used to construct each database. Primary differences between the 2 databases are an additional 5 years of ground-water withdrawal data, well locations in the updated database are restricted to Death Valley regional ground-water flow system model boundary, and application rates are from 0 to 1.5 feet per year lower than original estimates. The lower application rates result from revised estimates of crop consumptive use, which are based on updated estimates of potential evapotranspiration. In 2003, about 55,700 acre-feet of ground water was pumped in the DVRFS, of which 69 percent was used for irrigation, 13 percent for domestic, and 18 percent for public supply, commercial, and mining activities.

Michael T. Moreo; and Leigh Justet

2008-07-02T23:59:59.000Z

42

Implementation of a 3-D groundwater flow model in a semi-arid region using MODFLOW and GIS tools: The Zéramdine-Béni Hassen Miocene aquifer system (east-central Tunisia)  

Science Conference Proceedings (OSTI)

In this work, an integrated methodology was developed to investigate hydrological processes in Zeramdine-Beni Hassen Miocene aquifer and to validate the groundwater proprieties deduced from the geological, geophysical, hydrodynamic and hydrochemical ... Keywords: Geographic information system, Groundwater modeling, Hydrogeology, MODFLOW

Fethi Lachaal; Ammar Mlayah; Mourad BéDir; Jamila Tarhouni; Christian Leduc

2012-11-01T23:59:59.000Z

43

A Hydrostratigraphic Model and Alternatives for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 97: Yucca Flat-Climax Mine, Lincoln and Nye Counties, Nevada  

SciTech Connect

A new three-dimensional hydrostratigraphic framework model for the Yucca Flat-Climax Mine Corrective Action Unit was completed in 2005. The model area includes Yucca Flat and Climax Mine, former nuclear testing areas at the Nevada Test Site, and proximal areas. The model area is approximately 1,250 square kilometers in size and is geologically complex. Yucca Flat is a topographically closed basin typical of many valleys in the Basin and Range province. Faulted and tilted blocks of Tertiary-age volcanic rocks and underlying Proterozoic and Paleozoic sedimentary rocks form low ranges around the structural basin. During the Cretaceous Period a granitic intrusive was emplaced at the north end of Yucca Flat. A diverse set of geological and geophysical data collected over the past 50 years was used to develop a structural model and hydrostratigraphic system for the basin. These were integrated using EarthVision? software to develop the 3-dimensional hydrostratigraphic framework model. Fifty-six stratigraphic units in the model area were grouped into 25 hydrostratigraphic units based on each unit's propensity toward aquifer or aquitard characteristics. The authors organized the alluvial section into 3 hydrostratigraphic units including 2 aquifers and 1 confining unit. The volcanic units in the model area are organized into 13 hydrostratigraphic units that include 8 aquifers and 5 confining units. The underlying pre-Tertiary rocks are divided into 7 hydrostratigraphic units, including 3 aquifers and 4 confining units. Other units include 1 Tertiary-age sedimentary confining unit and 1 Mesozoic-age granitic confining unit. The model depicts the thickness, extent, and geometric relationships of these hydrostratigraphic units (''layers'' in the model) along with the major structural features (i.e., faults). The model incorporates 178 high-angle normal faults of Tertiary age and 2 low-angle thrust faults of Mesozoic age. The complexity of the model area and the non-uniqueness of some of the interpretations incorporated into the base model made it necessary to formulate alternative interpretations for some of the major features in the model. Five of these alternatives were developed so they could be modeled in the same fashion as the base model. This work was done for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office in support of the Underground Test Area subproject of the Environmental Restoration Project.

Geotechnical Sciences Group Bechtel Nevada

2006-01-01T23:59:59.000Z

44

A Hydrostratigraphic Framework Model and Alternatives for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 98: Frenchman Flat, Clark, Lincoln and Nye Counties, Nevada  

SciTech Connect

A new, revised three-dimensional (3-D) hydrostratigraphic framework model for Frenchman Flat was completed in 2004. The area of interest includes Frenchman Flat, a former nuclear testing area at the Nevada Test Site, and proximal areas. Internal and external reviews of an earlier (Phase I) Frenchman Flat model recommended additional data collection to address uncertainties. Subsequently, additional data were collected for this Phase II initiative, including five new drill holes and a 3-D seismic survey.

Bechtel Nevada

2005-09-01T23:59:59.000Z

45

Groundwater Impacts of Radioactive Wastes and Associated Environmental Modeling Assessment  

Science Conference Proceedings (OSTI)

This article provides a review of the major sources of radioactive wastes and their impacts on groundwater contamination. The review discusses the major biogeochemical processes that control the transport and fate of radionuclide contaminants in groundwater, and describe the evolution of mathematical models designed to simulate and assess the transport and transformation of radionuclides in groundwater.

Ma, Rui; Zheng, Chunmiao; Liu, Chongxuan

2012-11-01T23:59:59.000Z

46

PHAST Version 2--A Program for Simulating Groundwater Flow, Solute Transport, and  

E-Print Network (OSTI)

PHAST Version 2--A Program for Simulating Groundwater Flow, Solute Transport, and Multicomponent;COVER ILLUSTRATION: Results of PHAST simulation of the evolution of water chemistry in the Central 25 0 50 200 #12;PHAST Version 2--A Program for Simulating Groundwater Flow, Solute Transport

47

Heat Transport in Groundwater Systems--Laboratory Model  

E-Print Network (OSTI)

Solar energy is a possible alternate energy source for space heating. A method of economic long term solar energy storage is needed. Researchers have proposed storing solar energy by heating water using solar collectors and injecting the hot water into groundwater aquifers for long term energy storage. Of paramount importance to the success of such a system is the quality and the behavior of the aquifer used for hot water storage. In general, the problem is to obtain an accurate prediction of the response of an aquifer system and its basic components to the operation of a system of injection and pumping wells which are transporting water at a notably different temperature than the natural groundwater. The injection of hot water into a groundwater storage system will have a pronounced effect on the specific storage and mass flow within the aquifer. These effects will result from differences in viscosity, density, specific heat, and thermal conductivity between the injected water and the natural groundwater. A complex system of energy and mass transport will result, making analytical solutions unattainable or very complex. The objective of this study was to develop a numerical simulation which would predict the pressure and temperature of water in a groundwater system at any time in response to the pumping and injecting of hot and cold water. A numerical model was developed in which the groundwater flow equation and the energy transport equation are solved simultaneously using a finite difference approximation for the time derivative and three-dimensional Galerkin-finite element approximations for the space derivatives. The use of a strict Galerkin approach led to unacceptable solution oscillations in sharp temperature front problems (i.e., problems where the temperature changes quickly over a small distance or time). Several techniques were tried in an attempt to correct the problem. Reduction of element and time step size proved ineffective in eliminating the sharp temperature front oscillation problem. An upstream weighting scheme corrected the oscillation problem, but resulted in an unacceptable smear of the sharp temperature front. A mass lumping scheme resulted in the best solution to sharp temperature front problems. The mass lumping scheme yielded solutions without the oscillation problem and with less smear than the upstream weighting scheme.

Reed, D. B.; Reddell, D. L.

1980-08-01T23:59:59.000Z

48

Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test  

Science Conference Proceedings (OSTI)

Groundwater flow and radionuclide transport at the Shoal underground nuclear test are characterized using three-dimensional numerical models, based on site-specific hydrologic data. The objective of this modeling is to provide the flow and transport models needed to develop a contaminant boundary defining the extent of radionuclide-contaminated groundwater at the site throughout 1,000 years at a prescribed level of confidence. This boundary will then be used to manage the Project Shoal Area for the protection of the public and the environment.

K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley

2004-03-01T23:59:59.000Z

49

Hydrogeochemical Modelling for Groundwater in Neyveli Aquifer, Tamil Nadu, India, Using PHREEQC: A Case Study  

SciTech Connect

Sophisticated geochemical models have been used to describe and predict the chemical behaviour of complex natural waters and also to protect the groundwater resources from future contamination. One such model is used to study the hydrogeochemical complexity in a mine area. Extraction of groundwater from the coastal aquifer has been in progress for decades to mine lignite in Neyveli. This extraction has developed a cone of depression around the mine site. This cone of depression is well established by the geochemical nature of groundwater in the region. 42 groundwater samples were collected in a definite pattern and they were analysed for major cations, anions and trace elements. The saturation index (SI) of the groundwater for carbonate, sulphate and silica minerals was studied and it has been correlated with the recharge and the discharge regions. The SI of alumino silicates has been used to decipher the stage of weathering. The SI{sub Gibbsite} - SI{sub K-feldspar} has been spatially distributed and the regions of discharge and recharge were identified. Then two flow paths A1 and A2 were identified and inverse modelling using PHREEQC were carried out to delineate the geochemical process that has taken place from recharge to discharge. The initial and final solutions in both the flow paths were correlated with the thermodynamic silicate stability diagrams of groundwater and it was found that the state of thermodynamic stability of the end solutions along the flow path were approaching similar states of equilibrium at the discharge.

Chidambaram, S.; Anandhan, P. [Annamalai University, Department of Earth Sciences (India); Prasanna, M. V., E-mail: geoprasanna@gmail.com [Curtin University, Department of Applied Geology, School of Engineering and Science (Malaysia); Ramanathan, AL. [Jawaharlal Nehru University, School of Environmental Sciences (India); Srinivasamoorthy, K. [Pondicherry University, Department of Earth Sciences, School of Physical, Chemical and Applied Sciences (India); Senthil Kumar, G. [HNB Garwhal University, Department of Geology (India)

2012-09-15T23:59:59.000Z

50

Groundwater Data Modeling for Arc Hydro  

E-Print Network (OSTI)

During the years 1999–2002, a consortium for geographic information systems (GIS) in water resources, led by the Center for Research in Water Resources (CRWR) and the Environmental Systems Research Institute (ESRI), developed a data model, named Arc Hydro, for the presentation of surface water data in ArcGIS. This model was published in the summer of 2002 (Maidment, 2002) and has since been adopted as a common framework by data producing agencies, such as the USGS, and by creators of hydrologic models requiring GIS data such as the Hydrologic Engineering Center and the Danish Hydraulic Institute. The Design of Arc Hydro revealed that it is possible to define a “hydrologic information system ” which is a synthesis of geospatial and temporal data supporting hydrologic analysis and modeling (Maidment, 2002). This is an exciting new concept because rather than simply applying GIS in water resources, it provides a new way of thinking about how information technology can be used to support water resources planning, modeling and management. While the first Arc Hydro data model focused on describing surface water behavior, it has become apparent that a similar effort is needed to define an ArcGIS data model for groundwater, as part of Arc Hydro. This need is emphasized by the lack of a well understood and generally agreed

unknown authors

2003-01-01T23:59:59.000Z

51

Community College Highlights Paducah Site Groundwater Model | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Community College Highlights Paducah Site Groundwater Model Community College Highlights Paducah Site Groundwater Model Community College Highlights Paducah Site Groundwater Model May 8, 2013 - 12:00pm Addthis Steve Hampson of the University of Kentucky, left to right, West Kentucky Community & Technical College President Dr. Barbara Veazey, Paducah Junior College Board of Trustees member Ken Wheeler and Buz Smith of the DOE Paducah Site Office examine a DOE Paducah Site groundwater model exhibit at the West Kentucky Community & Technical College Emerging Technology Center. Steve Hampson of the University of Kentucky, left to right, West Kentucky Community & Technical College President Dr. Barbara Veazey, Paducah Junior College Board of Trustees member Ken Wheeler and Buz Smith of the DOE Paducah Site Office examine a DOE Paducah Site groundwater model exhibit at

52

Stable isotope and groundwater flow dynamics of agricultural irrigation recharge into groundwater resources of the Central Valley, California  

Science Conference Proceedings (OSTI)

Intensive agricultural irrigation and overdraft of groundwater in the Central Valley of California profoundly affect the regional quality and availability of shallow groundwater resources. In the natural state, the {delta}{sup 18}O values of groundwater were relatively homogeneous (mostly -7.0 {+-} 0.5{per_thousand}), reflecting local meteoric recharge that slowly (1-3m/yr) flowed toward the valley axis. Today, on the west side of the valley, the isotope distribution is dominated by high {sup 18}O enclosures formed by recharge of evaporated irrigation waters, while the east side has bands of low {sup 18}O groundwater indicating induced recharge from rivers draining the Sierra Nevada mountains. Changes in {delta}{sup 18}O values caused by the agricultural recharge strongly correlate with elevated nitrate concentrations (5 to >100 mg/L) that form pervasive, non-point source pollutants. Small, west-side cities dependent solely on groundwater resources have experienced increases of >1.0 mg/L per year of nitrate for 10-30 years. The resultant high nitrates threaten the economical use of the groundwater for domestic purposes, and have forced some well shut-downs. Furthermore, since >80% of modern recharge is now derived from agricultural irrigation, and because modern recharge rates are {approximately}10 times those of the natural state, agricultural land retirement by urbanization will severely curtail the current safe-yields and promote overdraft pumping. Such overdrafting has occurred in the Sacramento metropolitan area for {approximately}40 years, creating cones of depression {approximately}25m deep. Today, groundwater withdrawal in Sacramento is approximately matched by infiltration of low {sup 18}O water (-11.0{per_thousand}) away from the Sacramento and American Rivers, which is estimated to occur at 100-300m/year from the sharp {sup 18}O gradients in our groundwater isotope map.

Davisson, M.L.; Criss, R.E.

1995-01-01T23:59:59.000Z

53

Phase I Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 99: Rainier Mesa/Shoshone Mountain, Nevada Test Site, Nye County, Nevada, Revision 1  

SciTech Connect

This document presents a summary and framework of available transport data and other information directly relevant to the development of the Rainier Mesa/Shoshone Mountain (RMSM) Corrective Action Unit (CAU) 99 groundwater transport model. Where appropriate, data and information documented elsewhere are briefly summarized with reference to the complete documentation.

Nathan Bryant

2008-05-01T23:59:59.000Z

54

Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test  

SciTech Connect

The purpose of this work is to characterize groundwater flow and contaminant transport at the Shoal underground nuclear test through numerical modeling using site-specific hydrologic data. The ultimate objective is the development of a contaminant boundary, a model-predicted perimeter defining the extent of radionuclide-contaminated groundwater from the underground test throughout 1,000 years at a prescribed level of confidence. This boundary will be developed using the numerical models described here, after they are approved for that purpose by DOE and NDEP.

K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley

2004-03-01T23:59:59.000Z

55

Well data and groundwater flow direction problem: Steuben County, Indiana case study  

SciTech Connect

The rapid industrial growth in Northeastern Indiana has lead to the demand for more complete geologic information for Steuben County, Indiana by the citizenry. The information would allow environmental scientists, geologists and engineers to more accurately predict the potential migration and impact of pollutants on the soil and groundwater. As part of ongoing environmental site investigations in Steuben County, well data were collected from Indiana Department of Environmental management (IDEM) and the State of Indiana Department of Natural Resources to determine local and regional groundwater flow directions. Of the 162 registered wells in the study area, only 67 of them, that is, 41% of the data could be used. The remaining well data could not be used because of poor, inaccurate or incomplete information on the forms (i.e., location description, well log, elevation, etc.). The regional groundwater flow direction was northwest as would be expected from the topography. A groundwater divide or ridge that was implied from the local groundwater flow directions could not be confirmed due to poor well data. The determination of groundwater flow direction was made more complicated due to incomplete well logs from drillers. Increased industrial activities in the region could lead to greater potential for surface and groundwater pollution problems. It is recommended that well data be collected by qualified personnel (field geologists) during well drilling.

Goings, M.H. (ATEC Associates, Inc., Fort Wayne, IN (United States)); Isiorho, S.A. (Indiana Univ-Purdue Univ., Fort Wayne, IN (United States). Dept. of Geosciences)

1994-04-01T23:59:59.000Z

56

Evaluation of groundwater flow and transport at the Shoal underground nuclear test: An interim report  

Science Conference Proceedings (OSTI)

Since 1962, all United States nuclear tests have been conducted underground. A consequence of this testing has been the deposition of large amounts of radioactive materials in the subsurface, sometimes in direct contact with groundwater. The majority of this testing occurred on the Nevada Test Site, but a limited number of experiments were conducted in other locations. One of these is the subject of this report, the Project Shoal Area (PSA), located about 50 km southeast of Fallon, Nevada. The Shoal test consisted of a 12-kiloton-yield nuclear detonation which occurred on October 26, 1963. Project Shoal was part of studies to enhance seismic detection of underground nuclear tests, in particular, in active earthquake areas. Characterization of groundwater contamination at the Project Shoal Area is being conducted by the US Department of Energy (DOE) under the Federal Facility Agreement and Consent Order (FFACO) with the State of Nevada Department of Environmental Protection and the US Department of Defense (DOD). This order prescribes a Corrective Action Strategy (Appendix VI), which, as applied to underground nuclear tests, involves preparing a Corrective Action Investigation Plan (CAIP), Corrective Action Decision Document (CADD), Corrective Action Plan, and Closure Report. The scope of the CAIP is flow and transport modeling to establish contaminant boundaries that are protective of human health and the environment. This interim report describes the current status of the flow and transport modeling for the PSA.

Pohll, G.; Chapman, J.; Hassan, A.; Papelis, C.; Andricevic, R.; Shirley, C.

1998-07-01T23:59:59.000Z

57

Heat Transport in Groundwater Systems--Finite Element Model  

E-Print Network (OSTI)

Solar energy is a promising alternate energy source for space heating. A method of economic long term solar energy storage is needed. Researchers have proposed storing solar energy by injecting hot water heated using solar collectors into groundwater aquifers for long term energy storage. Analytical solutions are available that predict water temperatures as hot water is injected into a groundwater aquifer, but little field and laboratory data are available to verify these models. The objectives of this study were to construct a laboratory model to simulate hot water injection into a confined aquifer, to use data from the model to verify analytical solutions modeling this process, and to evaluate the effects of physical properties and design parameters on thermal recovery efficiency. Initial studies of hot water injection into underground reservoirs were done by the petroleum industry while studying secondary and tertiary oil recovery methods. These studies involved small laboratory models. Advances in computer technology made it possible to model these systems numerically. Many assumptions must be made to predict temperature distributions and thermal efficiencies using analytical models which are not required in numerical solutions. To simulate hot water injection into a confined aquifer, a laboratory model (a 1.8288 m deep, 0.2 radian sector tank, that was 7.01 m in the radial direction) was constructed. There were 39 temperature and 15 fluid pressure measuring locations through the model. Water was supplied to the model at a constant temperature and flow rate. The flow layer was composed of a fine grained Texblast blasting sand. Four runs were made. During the initial run, no heat transfer took place and the hydraulic conductivity was measured. Three runs were made where the heat transfer was monitored. Water level data from the heat transfer runs showed that as the temperature of the aquifer increased, the hydraulic conductivity increased. Temperature data indicated that the three radii closest to the well bore reached thermal equilibrium. The equilibrium temperature decreased as radius increased. From Run 1 to Run 2, the equilibrium temperature increased at each radius because a larger flow rate was used. A vertical thermal gradient existed in the flow layer with the less dense warm water floating out over the cooler more dense water initially in the model. During the pumping cycle, the temperatures gradually decreased. The temperature of the water as it was pumped out of the model was measured and the energy recovered was computed using the initial temperature as a reference. Various other temperatures were used as a base reference to calculate recovery efficiency. There were heat losses out the sides of the model. The assumption of angular symmetry made in all analytical solutions was therefore not met. For this reason, the analytical solutions showed adequate, but not great, agreement with the experimental temperature distributions. Using the analytical solutions, the effects of changing system design parameters were evaluated. Increasing thermal conductivity in the flow layer caused the temperature distribution to spread out but had no effect on thermal efficiency. Increasing the thermal conductivity in the confining layers caused the temperature profile to not move as far from the well, and decreased thermal efficiency. Injection rates are only indirectly related to thermal efficiency. The physical parameter having the greatest effect on thermal efficiency was the flow layer thickness. As thickness increased, thermal efficiency increased.

Grubaugh, E. K.; Reddell, D. L.

1980-08-01T23:59:59.000Z

58

Quasi-three dimensional ground-water modeling of the hydrologic influence of paleozoic rocks on the ground-water table at Yucca Mountain, Nevada  

E-Print Network (OSTI)

The proposed high-level radioactive waste repository site at Yucca Mountain, Nevada, has created a need to understand the, ground-water system at the site. One of the important hydrologic characteristics is a steep gradient on the ground-water table north of the repository site. This study investigates the cause of the steep gradient, based on the possible influence by Paleozoic rocks under the Yucca Mountain area. A quasi-three dimensional, steady-state, finite-difference model of the groundwater flow system of the Yucca Mountain Site and vicinity, was developed using a manual trial-and-error calibration technique to model the ground-water table. The ground-water system in the model was divided into a two layers, which consist of Cenozoic volcanic rocks and Paleozoic carbonate rocks. The carbonate rocks were defined to be a confined aquifer. The model simulates vertical flow from the volcanic rocks to the underlying carbonate rocks in an area where the Eleana Formation, a Paleozoic clastic aquitard, is absent. The model requires a vertical hydrologic connection in a particular region and a large difference in hydraulic heads between the volcanic rocks and the carbonates to create the steep gradient north of the repository site. The regions of different hydraulic gradient on the water-table surface could be simulated by spatial variations of the horizontal hydraulic conductivity in the volcanic rocks.

Lee, Si-Yong

1994-01-01T23:59:59.000Z

59

Analysis and Geochemical Modeling of Vanadium Contamination in Groundwater New Rifle Processing Site, Colorado  

Energy.gov (U.S. Department of Energy (DOE))

Analysis and Geochemical Modeling of Vanadium Contamination in Groundwater New Rifle Processing Site, Colorado

60

Phase II Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 98: Frenchman Flat, Nye County, Nevada, Rev. No.: 0  

Science Conference Proceedings (OSTI)

This report documents pertinent transport data and data analyses as part of the Phase II Corrective Action Investigation (CAI) for Frenchman Flat (FF) Corrective Action Unit (CAU) 98. The purpose of this data compilation and related analyses is to provide the primary reference to support parameterization of the Phase II FF CAU transport model.

DeNovio, Nicole M.; Bryant, Nathan; King, Chrissi B.; Bhark, Eric; Drellack, Sigmund L.; Pickens, John F.; Farnham, Irene; Brooks, Keely M.; Reimus, Paul; Aly, Alaa

2005-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Uranium Elemental and Isotopic Constraints on Groundwater Flow Beneath the Nopal I Uranium Deposit, Pena Blanca, Mexico  

SciTech Connect

The Nopal I uranium deposit in Chihuahua, Mexico, is an excellent analogue for evaluating the fate of spent fuel, associated actinides, and fission products over long time scales for the proposed Yucca Mountain high-level nuclear waste repository. In 2003, three groundwater wells were drilled directly adjacent to (PB-1) and 50 m on either side of the uranium deposit (PB-2 and PB-3) in order to evaluate uranium-series transport in three dimensions. After drilling, uranium concentrations were elevated in all of the three wells (0.1-18 ppm) due to drilling activities and subsequently decreased to {approx}5-20% of initial values over the next several months. The {sup 234}U/{sup 238}U activity ratios were similar for PB-1 and PB-2 (1.005 to 1.079) but distinct for PB-3 (1.36 to 1.83) over this time period, suggesting limited mixing between groundwater from these wells over these short time and length scales. Regional groundwater wells located up to several km from the deposit also have distinct uranium isotopic characteristics and constrain mixing over larger length and time scales. We model the decreasing uranium concentrations in the newly drilled wells with a simple one-dimensional advection-dispersion model, assuming uranium is introduced as a slug to each of the wells and transported as a conservative tracer. Using this model for our data, the relative uranium concentrations are dependent on both the longitudinal dispersion as well as the mean groundwater flow velocity. These parameters have been found to be correlated in both laboratory and field studies of groundwater velocity and dispersion (Klotz et al., 1980). Using typical relationships between velocity and dispersion for field and laboratory studies along with the relationship observed from our uranium data, both velocity (1-10 n/yr) and dispersion coefficient (1E-5 to 1E-2 cm{sup 2}/s) can be derived from the modeling. As discussed above, these relatively small flow velocities and dispersivities agree with mixing considerations derived from the {sup 234}U/{sup 238}U data. While these results and the limited productivity of these wells consistently suggest limited groundwater flow and mixing, we anticipate additional work with artificial tracers to better establish groundwater flow velocities and gradient at this site.

S.J. Goldstein; M.T. Murrell; A.M. Simmons

2005-07-11T23:59:59.000Z

62

Seasonal dynamics in costal aquifers : investigation of submarine groundwater discharge through field measurements and numerical models  

E-Print Network (OSTI)

The fresh and saline groundwater flowing from coastal aquifers into the ocean comprise submarine groundwater discharge (SGD). This outflow is an important pathway for the transport of nutrients and contaminants, and has ...

Michael, Holly Anne, 1976-

2005-01-01T23:59:59.000Z

63

Groundwater model calibration at Pantex using Data Fusion modeling  

SciTech Connect

The Pantex plant has operated as one of the Federal government`s key conventional and nuclear weapons facilities since the 1940`s. In recent years, the DOE has expended considerable effort to characterize the nature and extent of groundwater contamination associated with the site. That effort is still on-going with the ultimate aim of determining and implementing appropriate remedial measures. The goal of the study described in this report was to use Data Fusion modeling to calibrate a groundwater model near Zone 12 of Pantex, primarily to define the potential pathways to the Ogallala aquifer. Data Fusion is a new approach for combining different but interrelated types of information from multiple sources into a quantitative analysis of system characteristics and dynamic behavior. The Data Fusion Workstation (DFW) is a patented technique for carrying out Data Fusion analyses using specially developed computer based approaches. The technique results in the development of a calibrated model of a site consistent with the data, first principles, and geostatistical spatial continuity. A more explicit description of the Data Fusion concept and approach is presented.

NONE

1996-04-01T23:59:59.000Z

64

Multiphase Flow Modeling Research  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Science Chris Guenther, Director Computational Science Division RUA Spring Meeting, Morgantown, WV March 2013 2 NETL's Multiphase Flow Science Team * The Multiphase Flow Science Team develops physics-based simulation models to conduct applied scientific research. - Development of new theory - Extensive on-site and collaborative V&V efforts and testing - Engages in technology transfer - Applies the models to industrial scale problems. 3 Why is Multiphase Flow Science Needed? * Industry is increasingly relying on multiphase technologies to produce clean and affordable energy with carbon capture. * Unfortunately, the presence of a solid phase reduces the operating capacity of a typical energy device from its original design on average by 40% [1].

65

Review and selection of unsaturated flow models  

SciTech Connect

Since the 1960`s, ground-water flow models have been used for analysis of water resources problems. In the 1970`s, emphasis began to shift to analysis of waste management problems. This shift in emphasis was largely brought about by site selection activities for geologic repositories for disposal of high-level radioactive wastes. Model development during the 1970`s and well into the 1980`s focused primarily on saturated ground-water flow because geologic repositories in salt, basalt, granite, shale, and tuff were envisioned to be below the water table. Selection of the unsaturated zone at Yucca Mountain, Nevada, for potential disposal of waste began to shift model development toward unsaturated flow models. Under the US Department of Energy (DOE), the Civilian Radioactive Waste Management System Management and Operating Contractor (CRWMS M&O) has the responsibility to review, evaluate, and document existing computer models; to conduct performance assessments; and to develop performance assessment models, where necessary. This document describes the CRWMS M&O approach to model review and evaluation (Chapter 2), and the requirements for unsaturated flow models which are the bases for selection from among the current models (Chapter 3). Chapter 4 identifies existing models, and their characteristics. Through a detailed examination of characteristics, Chapter 5 presents the selection of models for testing. Chapter 6 discusses the testing and verification of selected models. Chapters 7 and 8 give conclusions and make recommendations, respectively. Chapter 9 records the major references for each of the models reviewed. Appendix A, a collection of technical reviews for each model, contains a more complete list of references. Finally, Appendix B characterizes the problems used for model testing.

Reeves, M.; Baker, N.A.; Duguid, J.O. [INTERA, Inc., Las Vegas, NV (United States)

1994-04-04T23:59:59.000Z

66

A Transient Numerical Simulation of Perched Ground-Water Flow at the Test Reactor Area, Idaho National Engineering and Environmental Laboratory, Idaho, 1952-94  

SciTech Connect

Studies of flow through the unsaturated zone and perched ground-water zones above the Snake River Plain aquifer are part of the overall assessment of ground-water flow and determination of the fate and transport of contaminants in the subsurface at the Idaho National Engineering and Environmental Laboratory (INEEL). These studies include definition of the hydrologic controls on the formation of perched ground-water zones and description of the transport and fate of wastewater constituents as they moved through the unsaturated zone. The definition of hydrologic controls requires stratigraphic correlation of basalt flows and sedimentary interbeds within the saturated zone, analysis of hydraulic properties of unsaturated-zone rocks, numerical modeling of the formation of perched ground-water zones, and batch and column experiments to determine rock-water geochemical processes. This report describes the development of a transient numerical simulation that was used to evaluate a conceptual model of flow through perched ground-water zones beneath wastewater infiltration ponds at the Test Reactor Area (TRA).

B. R. Orr (USGS)

1999-11-01T23:59:59.000Z

67

Temperature logging as an aid to understanding groundwater flow in boreholes  

SciTech Connect

Borehole temperatures are affected by a range of physical phenomena, including drilling and engineering procedures, thermal resistivity of the rock, surface climatic changes, local heat sources and sinks, free convection of the borehole fluid, and water flows inside the borehole. As a result, temperature logs provide unique information not available from other logs. On the other hand, because the temperature log is sensitive to a variety of phenomena, one or more of these may obscure the effect being studied. In the case where groundwater is entering the borehole at one depth and exiting at another depth (or at the surface) the temperature disturbance resulting from this flow is likely to be a prominent feature of the temperature profile of the borehole. Because of this, water flows in boreholes are often a source of noise in temperature logs, obscuring the features of interest. Recently, however, unusual groundwater behavior was noted in several boreholes at the Nevada Test Site (NTS), and temperature logs were run as part of a program to study this phenomenon. In this case the groundwater flow has been the feature of interest in the logs, and the logs have been useful as an aid in understanding the water flow in those boreholes.

Conaway, J.G.

1987-01-01T23:59:59.000Z

68

Updated Conceptual Model for the 300 Area Uranium Groundwater Plume  

SciTech Connect

The 300 Area uranium groundwater plume in the 300-FF-5 Operable Unit is residual from past discharge of nuclear fuel fabrication wastes to a number of liquid (and solid) disposal sites. The source zones in the disposal sites were remediated by excavation and backfilled to grade, but sorbed uranium remains in deeper, unexcavated vadose zone sediments. In spite of source term removal, the groundwater plume has shown remarkable persistence, with concentrations exceeding the drinking water standard over an area of approximately 1 km2. The plume resides within a coupled vadose zone, groundwater, river zone system of immense complexity and scale. Interactions between geologic structure, the hydrologic system driven by the Columbia River, groundwater-river exchange points, and the geochemistry of uranium contribute to persistence of the plume. The U.S. Department of Energy (DOE) recently completed a Remedial Investigation/Feasibility Study (RI/FS) to document characterization of the 300 Area uranium plume and plan for beginning to implement proposed remedial actions. As part of the RI/FS document, a conceptual model was developed that integrates knowledge of the hydrogeologic and geochemical properties of the 300 Area and controlling processes to yield an understanding of how the system behaves and the variables that control it. Recent results from the Hanford Integrated Field Research Challenge site and the Subsurface Biogeochemistry Scientific Focus Area Project funded by the DOE Office of Science were used to update the conceptual model and provide an assessment of key factors controlling plume persistence.

Zachara, John M.; Freshley, Mark D.; Last, George V.; Peterson, Robert E.; Bjornstad, Bruce N.

2012-11-01T23:59:59.000Z

69

Model Reduction and Parameter Estimation in Groundwater Modeling  

E-Print Network (OSTI)

Professor William W-G. Yeh, Chair Water resources systemsWilliam W-G. Yeh. Systems analysis in ground-water planningYeh (2012), Reduced order parameter estimation using quasilinearization and quadratic programming, Water

Siade, Adam

2012-01-01T23:59:59.000Z

70

Grand challenge problems in environmental modeling and remediation: Groundwater contaminant transport. Final project report 1998  

SciTech Connect

The over-reaching goal of the Groundwater Grand Challenge component of the Partnership in Computational Science (PICS) was to develop and establish the massively parallel approach for the description of groundwater flow and transport and to address the problem of uncertainties in the data and its interpretation. This necessitated the development of innovative algorithms and the implementation of massively parallel computational tools to provide a suite of simulators for groundwater flow and transport in heterogeneous media. This report summarizes the activities and deliverables of the Groundwater Grand Challenge project funded through the High Performance Computing grand challenge program of the Department of Energy from 1995 through 1997.

NONE

1998-04-01T23:59:59.000Z

71

HYDROLYZED WOOD SLURRY FLOW MODELING  

E-Print Network (OSTI)

LBL-10090 UC-61 HYDROLYZED WOOD SLURRY FLOW MODELING JimLBL-10090 HYDROLYZED WOOD SLURRY FLOW MODELING Jim Wrathallconversion of hydrolyzed wood slurry to fuel oil, Based on

Wrathall, Jim

2012-01-01T23:59:59.000Z

72

Modeling the Vulnerability of an Urban Groundwater System due to the Combined Impacts of Climate Change and Management Scenarios  

Science Conference Proceedings (OSTI)

Climate change impact on a groundwater-dependent small urban town has been investigated in the semiarid hard rock aquifer in southern India. A distributed groundwater model was used to simulate the groundwater levels in the study region for the ...

M. Sekhar; M. Shindekar; Sat K. Tomer; P. Goswami

2013-08-01T23:59:59.000Z

73

Modeling Turbulent Flow  

National Nuclear Security Administration (NNSA)

Turbulent Turbulent Flow with Implicit LES L.G. Margolin 1 Proceedings of the Joint Russian-American Five Laboratory Conference on Computational Mathematics/Physics 19-23 June, 2005 Vienna, Austria 1 Applied Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545, len@lanl.gov 1 Abstract Implicit large eddy simulation (ILES) is a methodology for modeling high Reynolds' num- ber flows that combines computational efficiency and ease of implementation with predictive calculations and flexible application. Although ILES has been used for more than fifteen years, it is only recently that significant effort has gone into providing a physical rationale that speaks to its capabilities and its limitations. In this talk, we will present new theoret- ical results aimed toward building a justification and discuss some remaining gaps in our understanding and our practical

74

Multiphase Flow Modeling Research  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Chris Guenther, Director Computational Science Division RUA Spring Meeting, Morgantown, WV March 2013 2 NETL's Multiphase Flow Science Team * The Multiphase Flow Science...

75

Groundwater Flow Systems at the Nevada Test Site, Nevada: A Synthesis of Potentiometric Contours, Hydrostratigraphy, and Geologic Structures  

Science Conference Proceedings (OSTI)

Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial-volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial-volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial-volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic gradients between aquifer types are downward throughout most of the study area; however, flow from the alluvial-volcanic aquifer into the underlying carbonate aquifer, where both aquifers are present, is believed to be minor because of an intervening confining unit. Limited exchange of water between aquifer types occurs by diffuse flow through the confining unit, by focused flow along fault planes, or by direct flow where the confining unit is locally absent. Interflow between regional aquifers is evaluated and mapped to define major flow paths. These flow paths delineate tributary flow systems, which converge to form intermediate and regional flow systems. The implications of these flow systems in controlling transport of radionuclides away from the underground test areas at the Nevada Test Site are briefly discussed. Additionally, uncertainties in the delineation of aquifers, the development of potentiometric contours, and the identification of flow systems are identified and evaluated. Eleven tributary flow systems and three larger flow systems are mapped in the Nevada Test Site area. Flow systems within the alluvial-volcanic aquifer dominate the western half of the study area, whereas flow systems within the carbonate aquifer are most prevalent in the southeastern half of the study area. Most of the flow in the regional alluvial-volcanic aquifer that moves through the underground testing area on Pahute Mesa is discharged to the land surface at springs and seeps in Oasis Valley. Flow in the regional carbonate aquifer is internally compartmentalized by major geologic structures, primarily thrust faults, which constrain flow into separate corridors. Contaminants that reach the regional carbonate aquifer from testing areas in Yucca and Frenchman Flats flow toward downgradient discharge areas through the Alkali Flat-Furnace Creek Ranch or Ash Meadows flow systems and their tributaries.

Fenelon, Joseph M.; Sweetkind, Donald S.; Laczniak, Randell J.

2010-01-25T23:59:59.000Z

76

UZ Flow Models and Submodels  

SciTech Connect

The purpose of this report is to document the unsaturated zone (UZ) flow models and submodels, as well as the flow fields that have been generated using the UZ flow model(s) of Yucca Mountain, Nevada. In this report, the term ''UZ model'' refers to the UZ flow model and the several submodels, which include tracer transport, temperature or ambient geothermal, pneumatic or gas flow, and geochemistry (chloride, calcite, and strontium) submodels. The term UZ flow model refers to the three-dimensional models used for calibration and simulation of UZ flow fields. This work was planned in the ''Technical Work Plan (TWP) for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Section 1.2.7). The table of included Features, Events, and Processes (FEPs), Table 6.2-11, is different from the list of included FEPs assigned to this report in the ''Technical Work Plan for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Table 2.1.5-1), as discussed in Section 6.2.6. The UZ model has revised, updated, and enhanced the previous UZ model (BSC 2001 [DIRS 158726]) by incorporating the repository design with new grids, recalibration of property sets, and more comprehensive validation effort. The flow fields describe fracture-fracture, matrix-matrix, and fracture-matrix liquid flow rates, and their spatial distributions as well as moisture conditions in the UZ system. These three-dimensional UZ flow fields are used directly by Total System Performance Assessment (TSPA). The model and submodels evaluate important hydrogeologic processes in the UZ as well as geochemistry and geothermal conditions. These provide the necessary framework to test hypotheses of flow and transport at different scales, and predict flow and transport behavior under a variety of climatic conditions. In addition, the limitations of the UZ model are discussed in Section 8.11.

Y. Wu

2004-11-01T23:59:59.000Z

77

The Influence of Groundwater Flow on Thermal Regimes in Mountainous Terrain  

DOE Green Energy (OSTI)

Active circulation of cool groundwater in mountainous terrain can cause an advective disturbance of the thermal regime. This factor complicates interpretation of data collected in geothermal exploration programs. An isothermal free-surface model has been developed which provides qualitative insight into the nature of an advective disturbance as it is affected by topography, permeability and climate. A fully coupled model of fluid and heat transfer is being developed for quantitative study of idealized mountain hydrothermal systems.

Forster, Craig; Smith, Leslie

1986-01-21T23:59:59.000Z

78

URANIUM-SERIES CONSTRAINTS ON RADIONUCLIDE TRANSPORT AND GROUNDWATER FLOW AT NOPAL I URANIUM DEPOSIT, SIERRA PENA BLANCA, MEXICO  

Science Conference Proceedings (OSTI)

Uranium-series data for groundwater samples from the vicinity of the Nopal I uranium ore deposit are used to place constraints on radionuclide transport and hydrologic processes at this site, and also, by analogy, at Yucca Mountain. Decreasing uranium concentrations for wells drilled in 2003 suggest that groundwater flow rates are low (uranium isotopic constraints also suggest that groundwater flow and mixing is limited at this site. The uranium isotopic systematics for water collected in the mine adit are consistent with longer rock-water interaction times and higher uranium dissolution rates at the front of the adit where the deposit is located. Short-lived nuclide data for groundwater wells are used to calculate retardation factors that are on the order of 1,000 for radium and 10,000 to 10,000,000 for lead and polonium. Radium has enhanced mobility in adit water and fractures near the deposit.

S. J. Goldstein, S. Luo, T. L. Ku, and M. T. Murrell

2006-04-01T23:59:59.000Z

79

URANIUM-SERIES CONSTRAINTS ON RADIONUCLIDE TRANSPORT AND GROUNDWATER FLOW AT NOPAL I URANIUM DEPOSIT, SIERRA PENA BLANCA, MEXICO  

SciTech Connect

Uranium-series data for groundwater samples from the vicinity of the Nopal I uranium ore deposit are used to place constraints on radionuclide transport and hydrologic processes at this site, and also, by analogy, at Yucca Mountain. Decreasing uranium concentrations for wells drilled in 2003 suggest that groundwater flow rates are low (< 10 m/yr). Field tests, well productivity, and uranium isotopic constraints also suggest that groundwater flow and mixing is limited at this site. The uranium isotopic systematics for water collected in the mine adit are consistent with longer rock-water interaction times and higher uranium dissolution rates at the front of the adit where the deposit is located. Short-lived nuclide data for groundwater wells are used to calculate retardation factors that are on the order of 1,000 for radium and 10,000 to 10,000,000 for lead and polonium. Radium has enhanced mobility in adit water and fractures near the deposit.

S. J. Goldstein, S. Luo, T. L. Ku, and M. T. Murrell

2006-04-01T23:59:59.000Z

80

Numerical Modeling of Coupled Groundwater and Surface Water Interactions in an Urban Setting  

Science Conference Proceedings (OSTI)

The Dominguez Channel Watershed (DCW), located in the southern portion of Los Angeles County (Figure A.1), drains about 345 square miles into the Los Angeles Harbor. The cities and jurisdictions in DCW are shown in Figure A.2. The largest of these include the cities of Los Angeles, Carson, and Torrance. This watershed is unique in that 93% of its land area is highly developed (i.e. urbanized). The watershed boundaries are defined by a complex network of storm drains and flood control channels, rather than being defined by natural topography. Table (1) shows a summary of different land uses in the Dominguez Channel Watershed (MEC, 2004). The Dominguez Watershed has the highest impervious area of all watersheds in the Los Angeles region. The more impervious the surface, the more runoff is generated during a storm. Storm water runoff can carry previously accumulated contaminants and transport them into receiving water systems. Point sources such as industrial wastewater and municipal sewage as well as urban runoff from commercial, residential, and industrial areas are all recognized as contributors to water quality degradation at DWC. Section 303(d) of the 1972 Federal Clean Water Act (CWA) requires states to identify and report all waters not meeting water quality standards and to develop action plans to pursue the water quality objectives. These plans specify the maximum amount of a given pollutant that the water body of concern can receive and still meet water quality standards. Such plans are called Total Maximum Daily Loads (TMDLs). TMDLs also specify allocations of pollutant loadings to point and non-point sources taking into account natural background pollutant levels. This demonstrates the importance of utilizing scientific tools, such as flow and transport models, to identify contaminant sources, understand integrated flow paths, and assess the effectiveness of water quality management strategies. Since overland flow is a very important component of the water balance and hydrology of DCW, a parallel, distributed watershed model that treats flow in groundwater and surface water in a dynamically coupled manner will be used to build a flow model of the watershed. This coupled model forms the basis for modeling and understanding the transport of contaminants through the Dominguez Channel Watershed, which can be used in designing and implementing TMDLs to manage the water quality in this basin. In this report, the coupled surface water-groundwater flow model of DCW will be presented. This flow model was calibrated against a storm that occurred in February 21st, 2004. The model and approach are explained further in the following sections.

Rihani, J F; Maxwell, R M

2007-09-26T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Simulations of Groundwater Flow and Radionuclide Transport in the Vadose and Saturated Zones beneath Area G, Los Alamos National Laboratory  

Science Conference Proceedings (OSTI)

Numerical simulations are used to predict the migration of radionuclides from the disposal units at Material Disposal Area G through the vadose zone and into the main aquifer in support of a radiological performance assessment and composite analysis for the site. The calculations are performed with the finite element code, FEHM. The transport of nuclides through the vadose zone is computed using a three-dimensional model that describes the complex mesa top geology of the site. The model incorporates the positions and inventories of thirty-four disposal pits and four shaft fields located at Area G as well as those of proposed future pits and shafts. Only three nuclides, C-14, Tc-99, and I-129, proved to be of concern for the groundwater pathway over a 10,000-year period. The spatial and temporal flux of these three nuclides from the vadose zone is applied as a source term for the three-dimensional saturated zone model of the main aquifer that underlies the site. The movement of these nuclides in the aquifer to a downstream location is calculated, and aquifer concentrations are converted to doses. Doses related to aquifer concentrations are six or more orders of magnitude lower than allowable Department of Energy performance objectives for low-level radioactive waste sites. Numerical studies were used to better understand vadose-zone flow through the dry mesa-top environment at Area G. These studies helped define the final model used to model flow and transport through the vadose zone. The study of transient percolation indicates that a steady flow vadose-zone model is adequate for computing contaminant flux to the aquifer. The fracture flow studies and the investigation of the effect of basalt and pumice properties helped us define appropriate hydrologic properties for the modeling. Finally, the evaporation study helped to justify low infiltration rates.

Kay H. Birdsell; Kathleen M. Bower; Andrew V. Wolfsberg; Wendy E. Soll; Terry A. Cherry; Tade W. Orr

1999-07-01T23:59:59.000Z

82

Review and selection of unsaturated flow models  

SciTech Connect

Under the US Department of Energy (DOE), the Civilian Radioactive Waste Management System Management and Operating Contractor (CRWMS M&O) has the responsibility to review, evaluate, and document existing computer ground-water flow models; to conduct performance assessments; and to develop performance assessment models, where necessary. In the area of scientific modeling, the M&O CRWMS has the following responsibilities: To provide overall management and integration of modeling activities. To provide a framework for focusing modeling and model development. To identify areas that require increased or decreased emphasis. To ensure that the tools necessary to conduct performance assessment are available. These responsibilities are being initiated through a three-step process. It consists of a thorough review of existing models, testing of models which best fit the established requirements, and making recommendations for future development that should be conducted. Future model enhancement will then focus on the models selected during this activity. Furthermore, in order to manage future model development, particularly in those areas requiring substantial enhancement, the three-step process will be updated and reported periodically in the future.

NONE

1993-09-10T23:59:59.000Z

83

DOEINVIl0845-51 DC-703 GROUNDWATER FLOW NEAR THE SHOAL SITE,  

Office of Legacy Management (LM)

DOEINVIl0845-51 DOEINVIl0845-51 DC-703 GROUNDWATER FLOW NEAR THE SHOAL SITE, SAND SPRINGS RANGE, NEVADA: IMPACT OF DENSITY-DRIVEN FLOW Prepared by Jenny Chapman, Todd Mihevc, and Alan McKay Submitted to Nevada Operations Office U.S. Department of Energy Las Vegas, Nevada September 1994 Publication #45130 This report was prepared as an account of work sponsored by the United States Government Neither the United States nor the United States Department of Energy, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, mark, manufacturer, or otherwise, does not necessarily

84

Evaluation of Collector Well Configurations to Model Hydrodynamics in Riverbank Filtration and Groundwater Remediation  

E-Print Network (OSTI)

Collector well designs are necessary to maximize groundwater uptake and riverbank filtration without negatively impacting an aquifer. Unfortunately, there is a lack of information and research regarding the implementation of collector well design parameters. In the past, collector well installation was too costly, but recent advances in well technology have made collector wells more cost effective. This research will contribute a set of guidelines to optimize riverbank filtration and groundwater remediation. This study models the hydrodynamics surrounding collector well configurations in riverbank filtration and groundwater remediation. Visual Modflow® was utilized to run a variety of numerical models to test four areas: flux along the laterals of a collector well, collector well interactions with a river, collector well yield, and collector well remediation capability. The two design parameters investigated were lateral length (25 m, 50 m, and 100 m) and number of laterals (3 and 4). The lateral flux tests confirm flux increases towards the terminal end of each lateral and pumping rate is the controlling factor in flux amount obtained along the laterals. The analysis of the flux-river interaction shows the main factor in determining flux amount is the initial river geometry, followed by the pumping rate, regional background flow, and collector well design, respectively. The models suggest that the 4-lateral collector well design is more effective than the 3-lateral design and in addition, 100 meter length laterals provide the highest amount of yield with the least amount of drawdown. The remediation tests investigate the application of vertical well equations to evaluate collector well designs in two areas: minimum pumping rate to capture line source of particles and first arrival time of particles. The remediation models show 100 meter length laterals provide both the lowest pumping rate and the highest residence time with the surrounding aquifer for maximum remediation. Ultimately, these models provide basic design guidelines and explain which designs are most effective, depending on the collector well purpose.

De Leon, Tiffany Lucinda

2010-08-01T23:59:59.000Z

85

Mathematical Modeling And Simulation For Fluid Flow In Porous Media  

E-Print Network (OSTI)

Mathematical models have been widely used to understand, predict, or optimize many complex physical processes. In particular, simulation of environmental effects of air polution is extensive. Here we address the need for using similar models to understand the fate and transport of groundwater contaminants and to design in situ remediation strategies. Three basic problem areas must be addressed in the modeling and simulation of the flow of groundwater contamination. One must first obtain an effective model to describe the complex fluid/fluid and fluid/rock interactions that control the transport of contaminants in groundwater. This includes the problems of determining and modeling the various multiphase or chemically reactive aspects of the problems which govern the flow of fluids, obtaining accurate reservoir descriptions at various length scales, and modeling the effects of this heterogeneity in the reservoir simulators. Next, one must develop accurate discretization techniques that retain the important physical properties of the continuous models without introducing spurious phenomena related to the discretization errors. Finally, one should develop efficient numerical solution algorithms that utilize the potential of the emerging computing architectures. We will discuss recent advances in each of these three areas.

Richard Ewing

2001-01-01T23:59:59.000Z

86

Modeling multiphase flow in porous medium systems at multiple scales.  

E-Print Network (OSTI)

??Problems involving multiphase flow and transport in porous media arise in a number of scientific and engineering applications including oil reservoir engineering and groundwater remediation.… (more)

Li, Huina.

2006-01-01T23:59:59.000Z

87

Importance of considering intraborehole flow in solute transport modeling under highly dynamic flow conditions  

SciTech Connect

Correct interpretation of tracer test data is critical for understanding transport processes in the subsurface. This task can be greatly complicated by the presence of intraborehole flows in a highly dynamic flow environment. At a new tracer test site (Hanford IFRC) a dynamic flow field created by changes in the stage of the adjacent Columbia River, coupled with a heterogeneous hydraulic conductivity distribution, leads to considerable variations in vertical hydraulic gradients. These variations, in turn, create intraborehole flows in fully-screened (6.5 m) observation wells with frequently alternating upward and downward movement. This phenomenon, in conjunction with a highly permeable aquifer formation and small horizontal hydraulic gradients, makes modeling analysis and model calibration a formidable challenge. Groundwater head data alone were insufficient to define the flow model boundary conditions, and the movement of the tracer was highly sensitive to the dynamics of the flow field. This study shows that model calibration can be significantly improved by explicitly considering (a) dynamic flow model boundary conditions and (b) intraborehole flow. The findings from this study underscore the difficulties in interpreting tracer tests and understanding solute transport under highly dynamic flow conditions.

Ma, Rui; Zheng, Chunmiao; Tonkin, Matthew J.; Zachara, John M.

2011-04-01T23:59:59.000Z

88

HYDROGEN ELECTROLYZER FLOW DISTRIBUTOR MODEL  

DOE Green Energy (OSTI)

The hybrid sulfur process (HyS) hydrogen electrolyzer consists of a proton exchange membrane (PEM) sandwiched between two porous graphite layers. An aqueous solution of sulfuric acid with dissolved SO{sub 2} gas flows parallel to the PEM through the porous graphite layer on the anode side of the electrolyzer. A flow distributor, consisting of a number of parallel channels acting as headers, promotes uniform flow of the anolyte fluid through the porous graphite layer. A numerical model of the hydraulic behavior of the flow distributor is herein described. This model was developed to be a tool to aid the design of flow distributors. The primary design objective is to minimize spatial variations in the flow through the porous graphite layer. The hydraulic data from electrolyzer tests consists of overall flowrate and pressure drop. Internal pressure and flow distributions are not measured, but these details are provided by the model. The model has been benchmarked against data from tests of the current electrolyzer. The model reasonably predicts the viscosity effect of changing the fluid from water to an aqueous solution of 30 % sulfuric acid. The permeability of the graphite layer was the independent variable used to fit the model to the test data, and the required permeability for a good fit is within the range literature values for carbon paper. The model predicts that reducing the number of parallel channels by 50 % will substantially improve the uniformity of the flow in the porous graphite layer, while maintaining an acceptable pressure drop across the electrolyzer. When the size of the electrolyzer is doubled from 2.75 inches square to 5.5 inches square, the same number of channels as in the current design will be adequate, but it is advisable to increase the channel cross-sectional flow area. This is due to the increased length of the channels.

Shadday, M

2006-09-28T23:59:59.000Z

89

Multiscale modeling in granular flow  

E-Print Network (OSTI)

Granular materials are common in everyday experience, but have long-resisted a complete theoretical description. Here, we consider the regime of slow, dense granular flow, for which there is no general model, representing ...

Rycroft, Christopher Harley

2007-01-01T23:59:59.000Z

90

Vulnerability assessment of groundwater resources: A modelling-based approach to the Mancha Occidental aquifer, Spain  

Science Conference Proceedings (OSTI)

The semiarid Mancha Occidental aquifer represents a paradigmatic case of intensive groundwater use for agriculture. Irrigation has proven a catalyst for welfare in the area over the last three decades, if at a significant environmental cost and while ... Keywords: Aquifer, Groundwater, Mancha Occidental, Participatory modelling, Vulnerability, Water Framework Directive

Pedro Martínez-Santos; M. Ramón Llamas; Pedro E. Martínez-Alfaro

2008-09-01T23:59:59.000Z

91

Effect of hydrological flow pattern on groundwater arsenic concentration in Bangladesh by Khandaker Ashfaque.  

E-Print Network (OSTI)

Widespread arsenic contamination of groundwater has become a major concern in Bangladesh since the water supply, particularly in rural areas, is heavily dependent on groundwater. However, relative to the extent of research ...

Ashfaque, Khandaker

2007-01-01T23:59:59.000Z

92

NUMERICAL MODEL FOR LAND SUBSIDENCE IN SHALLOW GROUNDWATER SYSTEMS  

E-Print Network (OSTI)

and R. L. Klausing, 1969, Land subsidence due to groundwater7612-10874 Fig. S. Land subsidence at Pixley, California:Symposium on Land Subsidence, Anaheim, CA, December 10-

Narasimhan, T.N.

2010-01-01T23:59:59.000Z

93

Conceptual Models for Migration of Key Groundwater Contaminants Through the Vadose Zone and Into the Upper Unconfined Aquifer Below the B-Complex  

Science Conference Proceedings (OSTI)

The B-Complex contains 3 major crib and trench disposal sites and 3 SST farms that have released nearly 346 mega-liters of waste liquids containing the following high groundwater risk drivers: ~14,000 kg of CN, 29,000 kg of Cr, 12,000 kg of U and 145 Ci of Tc-99. After a thorough review of available vadose zone sediment and pore water, groundwater plume, field gamma logging, field electrical resistivity studies, we developed conceptual models for which facilities have been the significant sources of the contaminants in the groundwater and estimated the masses of these contaminants remaining in the vadose zone and currently present in the groundwater in comparison to the totals released. This allowed us to make mass balance calculations on how consistent our knowledge is on the current deep vadose zone and groundwater distribution of contaminants. Strengths and weaknesses of the conceptual models are discussed as well as implications on future groundwater and deep vadose zone remediation alternatives. Our hypothesized conceptual models attribute the source of all of the cyanide and most of the Tc-99 currently in the groundwater to the BY cribs. The source of the uranium is the BX-102 tank overfill event and the source of most of the chromium is the B-7-A&B and B-8 cribs. Our mass balance estimates suggest that there are much larger masses of U, CN, and Tc remaining in the deep vadose zone within ~20 ft of the water table than is currently in the groundwater plumes below the B-Complex. This hypothesis needs to be carefully considered before future remediation efforts are chosen. The masses of these groundwater risk drivers in the the groundwater plumes have been increasing over the last decade and the groundwater plumes are migrating to the northwest towards the Gable Gap. The groundwater flow rate appears to flucuate in response to seasonal changes in hydraulic gradient. The flux of contaminants out of the deep vadose zone from the three proposed sources also appears to be transient such that the evolution of the contaminant plumes is transient.

Serne, R. Jeffrey; Bjornstad, Bruce N.; Keller, Jason M.; Thorne, Paul D.; Lanigan, David C.; Christensen, J. N.; Thomas, Gregory S.

2010-07-01T23:59:59.000Z

94

Modeling the vulnerability of an urban groundwater system due to the combined impacts of climate change and management scenarios  

Science Conference Proceedings (OSTI)

Climate change impact on a groundwater dependent small urban town has been investigated in the semi-arid hard rock aquifer in South India. A distributed groundwater model was used to simulate the groundwater levels in the study region for the ...

M. Sekhar; M. Shindekar; Sat K. Tomer; P. Goswami

95

Phase I Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nye County, Nevada, Revision 0  

Science Conference Proceedings (OSTI)

This report documents transport data and data analyses for Yucca Flat/Climax Mine CAU 97. The purpose of the data compilation and related analyses is to provide the primary reference to support parameterization of the Yucca Flat/Climax Mine CAU transport model. Specific task objectives were as follows: • Identify and compile currently available transport parameter data and supporting information that may be relevant to the Yucca Flat/Climax Mine CAU. • Assess the level of quality of the data and associated documentation. • Analyze the data to derive expected values and estimates of the associated uncertainty and variability. The scope of this document includes the compilation and assessment of data and information relevant to transport parameters for the Yucca Flat/Climax Mine CAU subsurface within the context of unclassified source-term contamination. Data types of interest include mineralogy, aqueous chemistry, matrix and effective porosity, dispersivity, matrix diffusion, matrix and fracture sorption, and colloid-facilitated transport parameters.

John McCord

2007-09-01T23:59:59.000Z

96

A screening model for simulating DNAPL flow and transport in porous media: theoretical development  

Science Conference Proceedings (OSTI)

In the last two decades there has been an increased awareness of the contamination of groundwater due to the presence of denser-than-water nonaqueous phase liquids (DNAPLs). Numerous theoretical, experimental and numerical investigations have been conducted ... Keywords: Contaminant transport, Multiphase flow, Screening model

Clinton S. Willson; James W. Weaver; Randall J. Charbeneau

2006-01-01T23:59:59.000Z

97

TOUGH2. Unsaturated Groundwater and Heat Transport Model  

DOE Green Energy (OSTI)

TOUGH2 is a new and improved version of TOUGH. TOUGH2 offers added capabilities and user features, including the flexibility to handle different fluid mixtures (water, water with tracer; water, CO2; water, air; water, air, with vapor pressure lowering and water, hydrogen), facilities for processing of geometric data (computational grids), and an internal version control system to ensure referenceability of code applications. TOUGH2 is a multi-dimensional numerical model for simulating the coupled transport of water, vapor, air, and heat in porous and fractured media. The program provides options for specifying injection or withdrawal of heat and fluids. Although primarily designed for studies of high-level nuclear waste isolation in partially saturated geological media, it should also be useful for a wider range of problems in heat and moisture transfer, and in the drying of porous materials. For example, geothermal reservoir simulation problems can be handled simply by setting the air mass function equal to zero on input. The TOUGH2 simulator was developed for problems involving strongly heat-driven flow. To describe these phenomena a multi-phase approach to fluid and heat flow is used, which fully accounts for the movement of gaseous and liquid phases, their transport of latent and sensible heat, and phase transitions between liquid and vapor. TOUGH2 takes account of fluid flow in both liquid and gaseous phases occurring under pressure, viscous, and gravity forces according to Darcy`s law. Interference between the phases is represented by means of relative permeability functions. The code handles binary, but not Knudsen, diffusion in the gas phase and capillary and phase adsorption effects for the liquid phase. Heat transport occurs by means of conduction with thermal conductivity dependent on water saturation, convection, and binary diffusion, which includes both sensible and latent heat.

Pruess, K. [Lawrence Berkeley National Lab., CA (United States)

1991-05-01T23:59:59.000Z

98

1.72 Groundwater Hydrology, Fall 2004  

E-Print Network (OSTI)

Fundamentals of subsurface flow and transport, emphasizing the role of groundwater in the hydrologic cycle, the relation of groundwater flow to geologic structure, and the management of contaminated groundwater. Topics ...

Harvey, Charles

99

Grand Challenge Problems in Environmental Modeling and Remediation: Groundwater Contaminant Transport (Partnerships in Computational Science)  

SciTech Connect

The over-reaching goal of the Groundwater Grand Challenge component of the Partnership in Computational Science (PICS) was to develop and establish the massively parallel approach for the description of groundwater flow and transport and to address the problem of uncertainties in the data and its interpretation. This necessitated the development of innovative algorithms and the implementation of massively parallel computational tools to provide a suite of simulators for groundwater flow and transport in heterogeneous media. This report summarizes the activities and deliverables of the University of South Carolina component of the Groundwater Grand Challenge project funded through the High Performance Computing grand challenge program of the Department of Energy from 1995 through 1997. Seven institutions were primarily involved in this project: Brookhaven National Laboratory, Oak Ridge National Laboratory, Princeton University, SUNY at Stony Brook, Texas A&M University, The University of South Carolina, and the University of Texas at Austin, with contributing efforts from the Westinghouse Savannah River Technology Center. Each institution had primary responsibility for specific research components, but strong collaboration among all institutions was essential for the success of the project and in producing the final deliverables. PICS deliverables include source code for the suite of research simulators and auxiliary HPC tools, associated documentation, and test problems. These materials will be available as indicated from each institution's web page or from the Center for Computational Sciences Oak Ridge National Laboratory in January 1998.

Sharpley, Robert C.

1997-12-01T23:59:59.000Z

100

Development of a Groundwater Management Model for the Project Shoal Area  

Science Conference Proceedings (OSTI)

This document describes the development of a user-friendly and efficient groundwater management model of the Project Shoal Area (PSA and surrounding area that will allow the U.S. Department of Energy and State of Nevada personnel to evaluate the impact of proposed water-use scenarios. The management model consists of a simple hydrologic model within an interactive groundwater management framework. This framework is based on an object user interface that was developed by the U.S. Geological Survey and has been used by the Desert Research Institute researchers and others to couple disparate environmental resource models, manage temporal and spatial data, and evaluate model results for management decision making. This framework was modified and applied to the PSA and surrounding Fairview Basin. The utility of the management model was demonstrated through the application of hypothetical future scenarios including mineral mining, regional expansion of agriculture, and export of water to large urban areas outside the region. While the results from some of the scenarios indicated potential impacts to groundwater levels near the PSA and others did not, together they demonstrate the utility of the management tool for the evaluation of proposed changes in groundwater use in or near the PSA.

G. Lamorey; S. Bassett; R. Schumer; D. Boyle; G. Pohll; J. Chapman

2006-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Modeling study for the implementation of in situ cometabolic bioremediation of trichloroethylene-contaminated groundwater. Master`s Thesis  

Science Conference Proceedings (OSTI)

The limitations of conventional groundwater remediation technologies have led to the development of innovative technologies which may achieve national hazardous waste site remediation goals. Before an innovative technology can be implemented in the field, remedial project managers, regulators and other stakeholders require adequate modeling tools to help assess the applicability of the technology at a particular site. This modeling study investigates how an innovative technology, in situ cometabolic bioremediation, might be implemented to remediate a TCE-contaminated site, under different site conditions. A steady-state model is developed which couples an analytical expression to simulate the effect of flow between multiple pumping and injection wells, with an expression to calculate TCE removal as groundwater circulates through in situ bioreactors established around the injection wells. Varying site conditions and well configurations are investigated to determine their effect on the overall treatment efficiency of a system. A dual screen well design is found to be an effective method for contaminant capture and treatment given typical values of anisotropy. Investigation of a multiple row implementation concept proves it to be an effective configuration for site cleanup. The model is integrated into interactive software which serves as a technology screening tool.

Christ, J.A.

1997-12-01T23:59:59.000Z

102

Groundwater chemistry along flow paths between a proposed repository site and the accessible environment  

Science Conference Proceedings (OSTI)

The Nevada Nuclear Waste Storage Investigations Program of the Department of Energy is investigating Yucca Mountain in the Nevada Test Site as a possible repository location. As part of this investigation, the groundwater from all pumped wells in and near the site has been sampled and analyzed; the results are reported in this document. The speciation and solubility of nuclear waste elements in these groundwaters have been calculated using the EQ3/6 computer code. Estimates have also been made of the pH and Eh buffering capacity of the water/rock system of Yucca Mountain.

Ogard, A.E.; Kerrisk, J.F.

1984-11-01T23:59:59.000Z

103

A Hybrid MPI/OpenMP Approach for Parallel Groundwater Model Calibration on Multicore Computers  

Science Conference Proceedings (OSTI)

Groundwater model calibration is becoming increasingly computationally time intensive. We describe a hybrid MPI/OpenMP approach to exploit two levels of parallelism in software and hardware to reduce calibration time on multicore computers with minimal parallelization effort. At first, HydroGeoChem 5.0 (HGC5) is parallelized using OpenMP for a uranium transport model with over a hundred species involving nearly a hundred reactions, and a field scale coupled flow and transport model. In the first application, a single parallelizable loop is identified to consume over 97% of the total computational time. With a few lines of OpenMP compiler directives inserted into the code, the computational time reduces about ten times on a compute node with 16 cores. The performance is further improved by selectively parallelizing a few more loops. For the field scale application, parallelizable loops in 15 of the 174 subroutines in HGC5 are identified to take more than 99% of the execution time. By adding the preconditioned conjugate gradient solver and BICGSTAB, and using a coloring scheme to separate the elements, nodes, and boundary sides, the subroutines for finite element assembly, soil property update, and boundary condition application are parallelized, resulting in a speedup of about 10 on a 16-core compute node. The Levenberg-Marquardt (LM) algorithm is added into HGC5 with the Jacobian calculation and lambda search parallelized using MPI. With this hybrid approach, compute nodes at the number of adjustable parameters (when the forward difference is used for Jacobian approximation), or twice that number (if the center difference is used), are used to reduce the calibration time from days and weeks to a few hours for the two applications. This approach can be extended to global optimization scheme and Monte Carol analysis where thousands of compute nodes can be efficiently utilized.

Tang, Guoping [ORNL; D'Azevedo, Ed F [ORNL; Zhang, Fan [ORNL; Parker, Jack C. [University of Tennessee, Knoxville (UTK); Watson, David B [ORNL; Jardine, Philip M [ORNL

2010-01-01T23:59:59.000Z

104

Development and evaluation of GIS-based ArcPRZM-3 system for spatial modeling of groundwater vulnerability to pesticide contamination  

Science Conference Proceedings (OSTI)

The objectives of this study were to develop and evaluate a GIS-based modeling system called ArcPRZM-3 for spatial modeling of pesticide leaching potential from soil surface towards groundwater. The ArcPRZM-3 was developed by coupling a commonly used ... Keywords: ArcPRZM-3, GIS, Groundwater, Groundwater spatial modeling, PRZM-3, Pesticide, Vulnerability assessment

Tahir Ali Akbar; Henry Lin; John DeGroote

2011-07-01T23:59:59.000Z

105

Stochastic hydro-economic modeling for optimal management of agricultural groundwater nitrate pollution under hydraulic conductivity uncertainty  

Science Conference Proceedings (OSTI)

In decision-making processes, reliability and risk aversion play a decisive role. This paper presents a framework for stochastic optimization of control strategies for groundwater nitrate pollution from agriculture under hydraulic conductivity uncertainty. ... Keywords: Fertilizer allocation, Groundwater, Nitrates, Optimization, Stochastic management model, Uncertainty

S. Peña-Haro; M. Pulido-Velazquez; C. Llopis-Albert

2011-08-01T23:59:59.000Z

106

Groundwater monitoring program plan and conceptual site model for the Al-Tuwaitha Nuclear Research Center in Iraq.  

Science Conference Proceedings (OSTI)

The Radiation Protection Center of the Iraqi Ministry of Environment is developing a groundwater monitoring program (GMP) for the Al-Tuwaitha Nuclear Research Center located near Baghdad, Iraq. The Al-Tuwaitha Nuclear Research Center was established in about 1960 and is currently being cleaned-up and decommissioned by Iraq's Ministry of Science and Technology. This Groundwater Monitoring Program Plan (GMPP) and Conceptual Site Model (CSM) support the Radiation Protection Center by providing:A CSM describing the hydrogeologic regime and contaminant issues,recommendations for future groundwater characterization activities, anddescriptions of the organizational elements of a groundwater monitoring program. The Conceptual Site Model identifies a number of potential sources of groundwater contamination at Al-Tuwaitha. The model also identifies two water-bearing zones (a shallow groundwater zone and a regional aquifer). The depth to the shallow groundwater zone varies from approximately 7 to 10 meters (m) across the facility. The shallow groundwater zone is composed of a layer of silty sand and fine sand that does not extend laterally across the entire facility. An approximately 4-m thick layer of clay underlies the shallow groundwater zone. The depth to the regional aquifer varies from approximately 14 to 17 m across the facility. The regional aquifer is composed of interfingering layers of silty sand, fine-grained sand, and medium-grained sand. Based on the limited analyses described in this report, there is no severe contamination of the groundwater at Al-Tuwaitha with radioactive constituents. However, significant data gaps exist and this plan recommends the installation of additional groundwater monitoring wells and conducting additional types of radiological and chemical analyses.

Copland, John Robin; Cochran, John Russell

2013-07-01T23:59:59.000Z

107

Groundwater monitoring program plan and conceptual site model for the Al-Tuwaitha Nuclear Research Center in Iraq.  

SciTech Connect

The Radiation Protection Center of the Iraqi Ministry of Environment is developing a groundwater monitoring program (GMP) for the Al-Tuwaitha Nuclear Research Center located near Baghdad, Iraq. The Al-Tuwaitha Nuclear Research Center was established in about 1960 and is currently being cleaned-up and decommissioned by Iraq's Ministry of Science and Technology. This Groundwater Monitoring Program Plan (GMPP) and Conceptual Site Model (CSM) support the Radiation Protection Center by providing:A CSM describing the hydrogeologic regime and contaminant issues,recommendations for future groundwater characterization activities, anddescriptions of the organizational elements of a groundwater monitoring program. The Conceptual Site Model identifies a number of potential sources of groundwater contamination at Al-Tuwaitha. The model also identifies two water-bearing zones (a shallow groundwater zone and a regional aquifer). The depth to the shallow groundwater zone varies from approximately 7 to 10 meters (m) across the facility. The shallow groundwater zone is composed of a layer of silty sand and fine sand that does not extend laterally across the entire facility. An approximately 4-m thick layer of clay underlies the shallow groundwater zone. The depth to the regional aquifer varies from approximately 14 to 17 m across the facility. The regional aquifer is composed of interfingering layers of silty sand, fine-grained sand, and medium-grained sand. Based on the limited analyses described in this report, there is no severe contamination of the groundwater at Al-Tuwaitha with radioactive constituents. However, significant data gaps exist and this plan recommends the installation of additional groundwater monitoring wells and conducting additional types of radiological and chemical analyses.

Copland, John Robin; Cochran, John Russell

2013-07-01T23:59:59.000Z

108

Probability distributions of hydraulic conductivity for the hydrogeologic units of the Death Valley regional ground-water flow system, Nevada and California  

Science Conference Proceedings (OSTI)

The use of geologic information such as lithology and rock properties is important to constrain conceptual and numerical hydrogeologic models. This geologic information is difficult to apply explicitly to numerical modeling and analyses because it tends to be qualitative rather than quantitative. This study uses a compilation of hydraulic-conductivity measurements to derive estimates of the probability distributions for several hydrogeologic units within the Death Valley regional ground-water flow system, a geologically and hydrologicaly complex region underlain by basin-fill sediments, volcanic, intrusive, sedimentary, and metamorphic rocks. Probability distributions of hydraulic conductivity for general rock types have been studied previously; however, this study provides more detailed definition of hydrogeologic units based on lithostratigraphy, lithology, alteration, and fracturing and compares the probability distributions to the aquifer test data. Results suggest that these probability distributions can be used for studies involving, for example, numerical flow modeling, recharge, evapotranspiration, and rainfall runoff. These probability distributions can be used for such studies involving the hydrogeologic units in the region, as well as for similar rock types elsewhere. Within the study area, fracturing appears to have the greatest influence on the hydraulic conductivity of carbonate bedrock hydrogeologic units. Similar to earlier studies, we find that alteration and welding in the Tertiary volcanic rocks greatly influence conductivity. As alteration increases, hydraulic conductivity tends to decrease. Increasing degrees of welding appears to increase hydraulic conductivity because welding increases the brittleness of the volcanic rocks, thus increasing the amount of fracturing.

Belcher, W.R.; Sweetkind, D.S.; Elliott, P.E.

2002-11-19T23:59:59.000Z

109

Development of a Coupled Groundwater–Atmosphere Model  

Science Conference Proceedings (OSTI)

Complete models of the hydrologic cycle have gained recent attention as research has shown interdependence between the coupled land and energy balance of the subsurface, land surface, and lower atmosphere. PF.WRF is a new model that is a ...

Reed M. Maxwell; Julie K. Lundquist; Jeffrey D. Mirocha; Steven G. Smith; Carol S. Woodward; Andrew F. B. Tompson

2011-01-01T23:59:59.000Z

110

Passenger Flow Model for Airline Networks  

Science Conference Proceedings (OSTI)

We present a model that rapidly finds an approximation of the expected passenger flow on an airline network, given forecast data concerning (1) the distribution of the demand for each itinerary, seen as a random variable; (2) the time distribution of ... Keywords: airline transportation, equilibrium model, passenger flow, recapture, spill

Jonathan Dumas; François Soumis

2008-05-01T23:59:59.000Z

111

Development of a Coupled Land Surface and Groundwater Model  

Science Conference Proceedings (OSTI)

Traditional land surface models (LSMs) used for numerical weather simulation, climate projection, and as inputs to water management decision support systems, do not treat the LSM lower boundary in a fully process-based fashion. LSMs have evolved ...

Reed M. Maxwell; Norman L. Miller

2005-06-01T23:59:59.000Z

112

News Release: DOE to Conduct Additional Groundwater Tests at Riverton  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

to Conduct Additional Groundwater Tests at to Conduct Additional Groundwater Tests at Riverton UMTRCA Site News Release: DOE to Conduct Additional Groundwater Tests at Riverton UMTRCA Site July 30, 2012 - 11:08am Addthis News Contact: Contractor, Judy Miller, S.M. Stoller Corporation Public Affairs (970) 248-6363 jmiller@lm.doe.gov Tests will indicate progress of current groundwater remediation strategy The U.S. Department of Energy will conduct additional characterization work at the Riverton, WY, Uranium Mill Tailings Radiation Control Act (UMTRCA) Site this summer, including extensive groundwater and soil sampling. The Department will use the sampling results to update the site conceptual model and to develop a revised groundwater flow and transport model to more accurately simulate natural flushing processes.

113

Efficient Production Optimization Using Flow Network Models  

E-Print Network (OSTI)

Reservoir simulation is an important tool for decision making and field development management. It enables reservoir engineers to predict reservoir production performance, update an existing model to reproduce monitoring data, assess alternative field development scenarios and design robust production optimization strategies by taking into account the existing uncertainties. A big obstacle in automating model calibration and production optimization approaches is the massive computation required to predict the response of real reservoirs under proposed changes in the model inputs. To speed up reservoir response predictions without compromising accuracy, fast surrogate models have been proposed. These models are either derived by preserving the physics of the involved processes (e.g. mass balance equations) to provide reliable long-range predictions or are developed based solely on statistical relations, in which case they can only provide short-range predictions due to the absence of the physical processes that govern the long-term behavior of the reservoir. We present an alternative solution that combines the advantages of both statistics-based and physics-based methods by deriving the flow predictions in complex two-dimensional models from one-dimensional flow network models. The existing injection/production wells in the original model form the nodes or vertices of the flow network. Each pair of wells (nodes) in the flow network is connected using a one-dimensional numerical simulation model; hence, the entire reservoir is reduced to a connected network of one-dimensional simulation models where the coupling between the individual one-dimensional models is enforced at the nodes where network edges intersect. The proposed flow network model provides a useful and fast tool for characterizing inter-well connectivity, estimating drainage volume between each pair of wells, and predicting reservoir production over an extended period of time for optimization purposes. We estimate the parameters of the flow network model using a robust training approach to ensure that the flow network model reproduces the response of the original full model under a wide range of development strategies. This step helps preserve the flow network model's predictive power during the production optimization when development strategies can change at different iterations. The robust networks training and the subsequent production optimization iterations are computationally efficient as they are performed with the faster flow network model. We demonstrate the effectiveness and applicability of our proposed flow network modeling approach to rapid production optimization using two-phase waterflooding simulations in synthetic and benchmark models.

Lerlertpakdee, Pongsathorn

2012-08-01T23:59:59.000Z

114

Building a geodatabase for mapping hydrogeological features and 3D modeling of groundwater systems: Application to the Saguenay-Lac-St.-Jean region, Canada  

Science Conference Proceedings (OSTI)

Understanding and managing groundwater resources require the integration of a large amount of high-quality data from a variety of sources. Due to the limitations in accessing information related to groundwater and subsurface conditions, the gathering ... Keywords: Arc Hydro Groundwater, ArcGIS, Hydrogeology, Hydrostructural modeling, Spatial database

Romain Chesnaux; Mélanie Lambert; Julien Walter; Ugo Fillastre; Murray Hay; Alain Rouleau; Réal Daigneault; Annie Moisan; Denis Germaneau

2011-11-01T23:59:59.000Z

115

Energy Flow Models for the Steel Industry  

E-Print Network (OSTI)

Energy patterns in the U. S. steel industry are examined using several models. First is an end-use model based on data in the 1994 Manufacturing Energy Consumption Survey (MECS). Then a seven-step process model is presented and material flow through each step is calibrated against Commerce Dept. data. Third, a detailed energy flow model is presented for coke ovens and blast furnaces, two very energy-intensive steps in our seven step model of steelmaking. This process-step model is calibrated against both our energy end use and material flow models. These models can serve as the base case for simulating changes in energy utilization and waste streams for steelmaking spurred by economic or regulatory conditions or technology innovations.

Hyman, B.; Andersen, J. P.

1998-04-01T23:59:59.000Z

116

A compressible flow model with capillary effects  

Science Conference Proceedings (OSTI)

A quasi-conservative formulation for compressible flows with interfaces including both capillary and viscous effects is developed. The model involves: (i) acoustic and convective transport; (ii) surface tension effects introduced as an extension of the ... Keywords: break-up, coalescence, compressibility, conservative formulation, interface capturing, mixture thermodynamics, surface tension, two-phase flows, viscosity

Guillaume Perigaud; Richard Saurel

2005-10-01T23:59:59.000Z

117

Self-potential modeling from primary flows  

DOE Green Energy (OSTI)

A new method for the calculation of self potentials (SP) based on induced current sources is presented. The induced current sources are due to divergences of the convective current which is driven, in turn, by a primary flow, either heat or fluid. Numerical modeling utilizing this method has been implemented using a two-dimensional transmission surface algorithm. When the primary flow is driven by the gradient of a potential, joint modeling of the primary flow and the resultant SP is possible with this algorithm. Examples of simple geometrical models in the presence of point sources for the primary flow are presented and discussed. Lastly, a field example of the joint modeling of temperature and SP data is illustrated with data from Red Hill Hot Spring, Utah.

Sill, W.R.

1981-03-01T23:59:59.000Z

118

Least-Cost Groundwater Remediation Using Uncertain Hydrogeological Information  

SciTech Connect

The design of groundwater remediation pump-and-treat well networks under aquifer parameter measurement uncertainty can be addressed using an optimal-design strategy based upon the concept of robust optimization. The robust-optimization approach allows for the admission of design alternatives that do not satisfy all design constraints. However in the selection process the algorithm penalizes such selections based upon the number of constraints violated. The result is a design which balances the importance of reliability with overall project cost. The robust-optimization method has been applied to the problem of groundwater plume containment and risk-based groundwater remediation design. Designs dedicated to groundwater-plume containment assure that the contaminant plume will not extend beyond a prespecified perimeter. Inwardly directed groundwater velocity must be achieved along this perimeter. The outer-approximation optimization technique in combination with a groundwater flow model ( PTC) is used to solve this optimal-design problem.

George F. Pinder; Karen Ricciardi; George P. Karatzas

2001-11-28T23:59:59.000Z

119

Scaled Experimental Modeling of VHTR Plenum Flows  

DOE Green Energy (OSTI)

Abstract The Very High Temperature Reactor (VHTR) is the leading candidate for the Next Generation Nuclear Power (NGNP) Project in the U.S. which has the goal of demonstrating the production of emissions free electricity and hydrogen by 2015. Various scaled heated gas and water flow facilities were investigated for modeling VHTR upper and lower plenum flows during the decay heat portion of a pressurized conduction-cooldown scenario and for modeling thermal mixing and stratification (“thermal striping”) in the lower plenum during normal operation. It was concluded, based on phenomena scaling and instrumentation and other practical considerations, that a heated water flow scale model facility is preferable to a heated gas flow facility and to unheated facilities which use fluids with ranges of density to simulate the density effect of heating. For a heated water flow lower plenum model, both the Richardson numbers and Reynolds numbers may be approximately matched for conduction-cooldown natural circulation conditions. Thermal mixing during normal operation may be simulated but at lower, but still fully turbulent, Reynolds numbers than in the prototype. Natural circulation flows in the upper plenum may also be simulated in a separate heated water flow facility that uses the same plumbing as the lower plenum model. However, Reynolds number scaling distortions will occur at matching Richardson numbers due primarily to the necessity of using a reduced number of channels connected to the plenum than in the prototype (which has approximately 11,000 core channels connected to the upper plenum) in an otherwise geometrically scaled model. Experiments conducted in either or both facilities will meet the objectives of providing benchmark data for the validation of codes proposed for NGNP designs and safety studies, as well as providing a better understanding of the complex flow phenomena in the plenums.

ICONE 15

2007-04-01T23:59:59.000Z

120

FEWA: a Finite Element model of Water flow through Aquifers  

Science Conference Proceedings (OSTI)

This report documents the implementation and demonstration of a Finite Element model of Water flow through Aquifers (FEWA). The particular features of FEWA are its versatility and flexibility to deal with as many real-world problems as possible. Point as well as distributed sources/sinks are included to represent recharges/pumpings and rainfall infiltrations. All sources/sinks can be transient or steady state. Prescribed hydraulic head on the Dirichlet boundaries and fluxes on Neumann or Cauchy boundaries can be time-dependent or constant. Source/sink strength over each element and node, hydraulic head at each Dirichlet boundary node, and flux at each boundary segment can vary independently of each other. Either completely confined or completely unconfined aquifers, or partially confined and partially unconfined aquifers can be dealt with effectively. Discretization of a compound region with very irregular curved boundaries is made easy by including both quadrilateral and triangular elements in the formulation. Large-field problems can be solved efficiently by including a pointwise iterative solution strategy as an optional alternative to the direct elimination solution method for the matrix equation approximating the partial differential equation of groundwater flow. FEWA also includes transient flow through confining leaky aquifers lying above and/or below the aquifer of interest. The model is verified against three simple cases to which analytical solutions are available. It is then demonstrated by two examples of how the model can be applied to heterogeneous and anisotropic aquifers with transient boundary conditions, time-dependent sources/sinks, and confining aquitards for a confined aquifer of variable thickness and for a free surface problem in an unconfined aquifer, respectively. 20 references, 25 figures, 8 tables.

Yeh, G.T.; Huff, D.D.

1983-11-01T23:59:59.000Z

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121

ESS 2012 Peer Review - Flow Battery Modeling - Soowhan Kim, PNNL  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Pacific Northwest National Laboratory, vilayanur.viswanathan@pnnl.gov Flow Battery Modeling (a) (b) Developed shunt and flow models were used to successfully develop a...

122

DOE Hydrogen Analysis Repository: FLOW Model  

NLE Websites -- All DOE Office Websites (Extended Search)

FLOW Model FLOW Model Project Summary Full Title: Chemical Engineering Process Simulation Platform - FLOW Project ID: 131 Principal Investigator: Juan Ferrada Brief Description: FLOW is a steady-state chemical process simulator. Modules have been developed for supply chain calculations, micro-economic calculations, and other calculations. Purpose Simulate steady-state chemical processes to support hydrogen infrastructure and transition analysis. Performer Principal Investigator: Juan Ferrada Organization: Oak Ridge National Laboratory (ORNL) Address: Bethel Valley 1, Bldg 5700, N217 Oak Ridge, TN 37831-6166 Telephone: 865-574-4998 Email: ferradajj@ornl.gov Sponsor(s) Name: Fred Joseck Organization: DOE Hydrogen Program Telephone: 202-586-7932 Email: Fred.Joseck@ee.doe.gov

123

Improved modeling techniques for turbomachinery flow fields  

DOE Green Energy (OSTI)

This program has the objective of developing an improved methodology for modeling turbomachinery flow fields, including the prediction of losses and efficiency. Specifically, the program addresses the treatment of the mixing stress tensor terms attributed to deterministic flow field mechanisms required in steady-state Computational Fluid Dynamic (CFD) models for turbomachinery flow fields. These mixing stress tensors arise due to spatial and temporal fluctuations (in an absolute frame of reference) caused by rotor-stator interaction due to various blade rows and by blade-to-blade variation of flow properties. This will be accomplished in a cooperative program by Penn State University and the Allison Engine Company. These tasks include the acquisition of previously unavailable experimental data in a high-speed turbomachinery environment, the use of advanced techniques to analyze the data, and the development of a methodology to treat the deterministic component of the mixing stress tenor.

Lakshminarayana, B.; Fagan, J.R. Jr.

1995-12-31T23:59:59.000Z

124

Status of understanding of the saturated-zone ground-water flow system at Yucca Mountain, Nevada, as of 1995  

SciTech Connect

Yucca Mountain, which is being studied extensively because it is a potential site for a high-level radioactive-waste repository, consists of a thick sequence of volcanic rocks of Tertiary age that are underlain, at least to the southeast, by carbonate rocks of Paleozoic age. Stratigraphic units important to the hydrology of the area include the alluvium, pyroclastic rocks of Miocene age (the Timber Mountain Group; the Paintbrush Group; the Calico Hills Formation; the Crater Flat Group; the Lithic Ridge Tuff; and older tuffs, flows, and lavas beneath the Lithic Ridge Tuff), and sedimentary rocks of Paleozoic age. The saturated zone generally occurs in the Calico Hills Formation and stratigraphically lower units. The saturated zone is divided into three aquifers and two confining units. The flow system at Yucca Mountain is part of the Alkali Flat-Furnace Creek subbasin of the Death Valley groundwater basin. Variations in the gradients of the potentiometric surface provided the basis for subdividing the Yucca Mountain area into zones of: (1) large hydraulic gradient where potentiometric levels change at least 300 meters in a few kilometers; (2) moderate hydraulic gradient where potentiometric levels change about 45 meters in a few kilometers; and (3) small hydraulic gradient where potentiometric levels change only about 2 meters in several kilometers. Vertical hydraulic gradients were measured in only a few boreholes around Yucca Mountain; most boreholes had little change in potentiometric levels with depth. Limited hydraulic testing of boreholes in the Yucca Mountain area indicated that the range in transmissivity was more than 2 to 3 orders of magnitude in a particular hydrogeologic unit, and that the average values for the individual hydrogeologic units generally differed by about 1 order of magnitude. The upper volcanic aquifer seems to be the most permeable hydrogeologic unit, but this conclusion was based on exceedingly limited data.

Luckey, R.R.; Tucci, P.; Faunt, C.C.; Ervin, E.M. [and others

1996-12-31T23:59:59.000Z

125

Mathematical Model for Efficient Water Flow Curic Vladimir  

E-Print Network (OSTI)

Industry, Mathematical and Computer Modelling, 39, pp. 1353- 1374, 2004 [6] Jeppson R. Analysis of flow

Krejiæ, Nata�a

126

2000 Annual Interim Sanitary Landfill Groundwater Monitoring Report  

Science Conference Proceedings (OSTI)

This report includes a discussion of the groundwater flow direction and rate, the groundwater analytical results, and the methane monitoring results.

Chase, J.A.

2001-01-26T23:59:59.000Z

127

Modelling the remediation of contaminated groundwater using zero-valent iron barrier  

Science Conference Proceedings (OSTI)

This paper presents results of modelling studies on remediation of groundwater contaminated with uranium using a zero-valent iron permeable reactive barrier (ZVI PRB) at the U.S. Oak Ridge Y-12 site that are used to establish modelling techniques that are of value to other sites such as in the UK. A systematic modelling methodology has been developed to study the problem by using a suite of modelling tools. Firstly a conceptual basis of the main chemical processes representing the remediation of uranium by the ZVI PRB is developed. Two main effects involving reduction and corrosion have been identified as being relevant for the remediation processes. These are then formulated and implemented using the reactive chemical model PHREEQC to provide underpinning chemical input parameters for subsequent reactive solute transport modelling using the TRAFFIC and PHAST codes. Initial results shows that modelling can be a very cost-effective means to study the hydrogeological and geochemical processes involved and to aid understanding of the remediation concept. The modelling approaches presented and lessons learnt are thought to be relevant to other cases of contaminated land study and are likely to be of value to site management concepts which consider on-site disposal of contaminated soils and materials. (authors)

Kwong, S.; Small, J.; Tahar, B. [Nexia Solutions Ltd., Hinton House, Risley, Warrington, WA (United Kingdom)

2007-07-01T23:59:59.000Z

128

Data Package for Past and Current Groundwater Flow and Contamination beneath Single-Shell Tank Waste Management Areas  

Science Conference Proceedings (OSTI)

This appendix summarizes historic and recent groundwater data collected from the uppermost aquifer beneath the 200 East and 200 West Areas. Although the area of interest is the Hanford Site Central Plateau, most of the information discussed in this appendix is at the scale of individual single-shell tank waste management areas. This is because the geologic, and thus the hydraulic, properties and the geochemical properties (i.e., groundwater composition) are different in different parts of the Central Plateau.

Horton, Duane G.

2007-03-16T23:59:59.000Z

129

On Water Flow in Hot Fractured Rock -- A Sensitivity Study on the Impact of Fracture-Matrix Heat Transfer  

E-Print Network (OSTI)

Flow calculations for Yucca Mountain groundwater travelunsaturated model of Yucca Mountain, Nevada, Journal ofinto drifts at Yucca Mountain, Journal of Contaminant

Birkholzer, Jens T.; Zhang, Yingqi

2005-01-01T23:59:59.000Z

130

Continuum modeling of two-phase flows  

SciTech Connect

Continuum modeling of two-phase flows can essentially be achieved in two ways. The first approach, the so-called continuum theory of mixtures, ignores the details of the flow occurring on the microscopic level, while the second one is the result of some averaging procedure. Although they both lead, as expected, to the same set of basic equations, they differ strongly in their spirit when closure equations have to be found. In the present report, we have attempted to give a brief critical review of both approaches, to compare them and to discuss some of the major difficulties which arise. It is shown that the application of the continuum theory of mixtures is, in most cases, questionable and that the only appropriate way of finding closure equations, besides correlating experimental results, consists in a useful investigation of the microscopic flow pattern associated with an adequate averaging technique.

Bataille, J.; Kestin, J.

1981-12-01T23:59:59.000Z

131

Radiogenic and Stable Isotope and Hydrogeochemical Investigation of Groundwater, Pajarito Plateau and Surrounding Areas, New Mexico  

Science Conference Proceedings (OSTI)

From October 2004 through February 2006, Los Alamos National Laboratory, the New Mexico Environment Department-Department of Energy Oversight Bureau, and the United States Geological Survey conducted a hydrochemical investigation. The purpose of the investigation was to evaluate groundwater flow paths and determine groundwater ages using tritium/helium-3 and carbon-14 along with aqueous inorganic chemistry. Knowledge of groundwater age and flow paths provides a technical basis for selecting wells and springs for monitoring. Groundwater dating is also relevant to groundwater resource management, including aquifer sustainability, especially during periods of long-term drought. At Los Alamos, New Mexico, groundwater is either modern (post-1943), submodern (pre-1943), or mixed (containing both pre- and post-1943 components). The regional aquifer primarily consists of submodern groundwater. Mixed-age groundwater results from initial infiltration of surface water, followed by mixing with perched alluvial and intermediate-depth groundwater and the regional aquifer. No groundwater investigation is complete without using tritium/helium-3 and carbon-14 dating methods to quantify amounts of modern, mixed, and/or submodern components present in samples. Computer models of groundwater flow and transport at Los Alamos should be calibrated to groundwater ages for perched intermediate zones and the regional aquifer determined from this investigation. Results of this study clearly demonstrate the occurrence of multiple flow paths and groundwater ages occurring within the Sierra de los Valles, beneath the Pajarito Plateau, and at the White Rock Canyon springs. Localized groundwater recharge occurs within several canyons dissecting the Pajarito Plateau. Perched intermediate-depth groundwater and the regional aquifer beneath Pueblo Canyon, Los Alamos Canyon, Sandia Canyon, Mortandad Canyon, Pajarito Canyon, and Canon de Valle contain a modern component. This modern component consists of tritium, nitrate, perchlorate, chromate, boron, uranium, and/or high explosive compounds. It is very unlikely that there is only one transport or travel time, ranging from 25 to 62 years, for these conservative chemicals migrating from surface water to the regional water table. Lengths of groundwater flow paths vary within deep saturated zones containing variable concentrations of tritium. The 4-series springs discharging within White Rock Canyon contain a modern component of groundwater, primarily tritium. Average groundwater ages for the regional aquifer beneath the Pajarito Plateau varied from 565 to 10,817 years, based on unadjusted carbon-14 measurements.

Patrick Longmire, Michael Dale, Dale Counce, Andrew Manning, Toti Larson, Kim Granzow, Robert Gray, and Brent Newman

2007-07-15T23:59:59.000Z

132

An adaptive sparse-grid high-order stochastic collocation method for Bayesian inference in groundwater reactive transport modeling  

SciTech Connect

Although Bayesian analysis has become vital to the quantification of prediction uncertainty in groundwater modeling, its application has been hindered due to the computational cost associated with numerous model executions needed for exploring the posterior probability density function (PPDF) of model parameters. This is particularly the case when the PPDF is estimated using Markov Chain Monte Carlo (MCMC) sampling. In this study, we develop a new approach that improves computational efficiency of Bayesian inference by constructing a surrogate system based on an adaptive sparse-grid high-order stochastic collocation (aSG-hSC) method. Unlike previous works using first-order hierarchical basis, we utilize a compactly supported higher-order hierar- chical basis to construct the surrogate system, resulting in a significant reduction in the number of computational simulations required. In addition, we use hierarchical surplus as an error indi- cator to determine adaptive sparse grids. This allows local refinement in the uncertain domain and/or anisotropic detection with respect to the random model parameters, which further improves computational efficiency. Finally, we incorporate a global optimization technique and propose an iterative algorithm for building the surrogate system for the PPDF with multiple significant modes. Once the surrogate system is determined, the PPDF can be evaluated by sampling the surrogate system directly with very little computational cost. The developed method is evaluated first using a simple analytical density function with multiple modes and then using two synthetic groundwater reactive transport models. The groundwater models represent different levels of complexity; the first example involves coupled linear reactions and the second example simulates nonlinear ura- nium surface complexation. The results show that the aSG-hSC is an effective and efficient tool for Bayesian inference in groundwater modeling in comparison with conventional MCMC sim- ulations. The computational efficiency is expected to be more beneficial to more computational expensive groundwater problems.

Zhang, Guannan [ORNL; Webster, Clayton G [ORNL; Gunzburger, Max D [ORNL

2012-09-01T23:59:59.000Z

133

Lattice Boltzmann modeling of microchannel flow in slip flow regime  

Science Conference Proceedings (OSTI)

We present the lattice Boltzmann equation (LBE) with multiple relaxation times (MRT) to simulate pressure-driven gaseous flow in a long microchannel. We obtain analytic solutions of the MRT-LBE with various boundary conditions for the incompressible ... Keywords: Gas flow through microchannel, Lattice Boltzmann equation with multiple relaxation times, Slip flow

Frederik Verhaeghe; Li-Shi Luo; Bart Blanpain

2009-01-01T23:59:59.000Z

134

Modelling Information Flows in Financial Markets  

E-Print Network (OSTI)

This paper presents an overview of information-based asset pricing. In this approach, an asset is defined by its cash-flow structure. The market is assumed to have access to "partial" information about future cash flows. Each cash flow is determined by a collection of independent market factors called X-factors. The market filtration is generated by a set of information processes, each of which carries information about one of the X-factors, and eventually reveals the X-factor. Each information process has two terms, one of which contains a "signal" about the associated X-factor, and the other of which represents "market noise". The price of an asset is given by the expectation of the discounted cash flows in the risk-neutral measure, conditional on the information provided by the market. When the market noise is modelled by a Brownian bridge one is able to construct explicit formulae for asset prices, as well as semi-analytic expressions for the prices and greeks of options and derivatives. In particular, op...

Brody, Dorje C; Macrina, Andrea

2010-01-01T23:59:59.000Z

135

Shock Scattering in Multiphase Flow Model  

Science Conference Proceedings (OSTI)

Multiphase flow models have been proposed for use in situations which have combined Rayleigh-Taylor (RTI) and Richtmyer-Meshkov (RMI) instabilities. Such an approach works poorly for the case of a heavy to light shock incidence on a developed interface. The physical original of this difficulty is traced to an inadequate model of the interfacial pressure term as it appears in the momentum and turbulence kinetic energy equations. Constraints on the form of a better model from a variety of sources are considered. In this context it is observed that a new constraint on closures arises. This occurs because of the discontinuity within the shock responsible for the RMI. The proposed model (Shock Scattering) is shown to give useful results.

Klem, D

2003-10-16T23:59:59.000Z

136

Shock Scattering in a Multiphase Flow Model  

Science Conference Proceedings (OSTI)

Multiphase flow models have been proposed for use in situations which have combined Rayleigh-Taylor (RTI) and Richtmyer-Meshkov (RMI) instabilities. Such an approach work poorly for the case of a heavy to light shock incidence on a developed interface. The physical original of this difficulty is traced to an inadequate model of the interfacial pressure term as it appears in the momentum and turbulence kinetic energy equations. Constraints on the form of a better model from a variety of sources are considered. In this context it is observed that a new constraint on closures arises. This occurs because of the discontinuity within the shock responsible for the RMI. The proposed model (Shock Scattering) is shown to give useful results.

Klem, D

2003-04-08T23:59:59.000Z

137

Secondary Flow and Upstream Dynamics in Double Bifurcation Model  

E-Print Network (OSTI)

Flow behavior in bifurcation models is of great importance to health risk assessments and pulmonary drug delivery. This is particularly true of secondary flow behavior in multi-bifurcation models. Previously, both numerical ...

Leong, Fong Yew

138

Observing and modeling Earths energy flows  

SciTech Connect

This article reviews, from the authors perspective, progress in observing and modeling energy flows in Earth's climate system. Emphasis is placed on the state of understanding of Earth's energy flows and their susceptibility to perturbations, with particular emphasis on the roles of clouds and aerosols. More accurate measurements of the total solar irradiance and the rate of change of ocean enthalpy help constrain individual components of the energy budget at the top of the atmosphere to within {+-}2 W m{sup -2}. The measurements demonstrate that Earth reflects substantially less solar radiation and emits more terrestrial radiation than was believed even a decade ago. Active remote sensing is helping to constrain the surface energy budget, but new estimates of downwelling surface irradiance that benefit from such methods are proving difficult to reconcile with existing precipitation climatologies. Overall, the energy budget at the surface is much more uncertain than at the top of the atmosphere. A decade of high-precision measurements of the energy budget at the top of the atmosphere is providing new opportunities to track Earth's energy flows on timescales ranging from days to years, and at very high spatial resolution. The measurements show that the principal limitation in the estimate of secular trends now lies in the natural variability of the Earth system itself. The forcing-feedback-response framework, which has developed to understand how changes in Earth's energy flows affect surface temperature, is reviewed in light of recent work that shows fast responses (adjustments) of the system are central to the definition of the effective forcing that results from a change in atmospheric composition. In many cases, the adjustment, rather than the characterization of the compositional perturbation (associated, for instance, with changing greenhouse gas concentrations, or aerosol burdens), limits accurate determination of the radiative forcing. Changes in clouds contribute importantly to this adjustment and thus contribute both to uncertainty in estimates of radiative forcing and to uncertainty in the response. Models are indispensable to calculation of the adjustment of the system to a compositional change but are known to be flawed in their representation of clouds. Advances in tracking Earth's energy flows and compositional changes on daily through decadal timescales are shown to provide both a critical and constructive framework for advancing model development and evaluation.

Stevens B.; Schwartz S.

2012-05-11T23:59:59.000Z

139

Groundwater Database | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Groundwater Database Groundwater Database Groundwater Database DOE has one of the largest ground water contamination problems and subsequent cleanup responsibilities for a single entity in the world, in terms of the sheer volume of affected groundwater, number of plumes, range of hydrogeologic settings, and diversity of contaminant types. The Groundwater Database was developed to provide a centralized location for information relating to groundwater flow, contamination, and remedial approaches across the DOE complex. The database provides DOE management and other interested parties with an easily accessible, high level understanding of the type of contamination, magnitude of contamination, and dynamics of groundwater systems at DOE sites. It also identifies remedial approaches, exit strategies, long-term stewardship requirements, regulatory

140

Hanford Site ground-water monitoring for 1994  

SciTech Connect

This report presents the results of the Ground-Water Surveillance Project monitoring for calendar year 1994 on the Hanford Site, Washington. Hanford Site operations from 1943 onward produced large quantities of radiologic and chemical waste that have impacted ground-water quality on the Site. Monitoring of water levels and ground-water chemistry is performed to track the extent of contamination and trends in contaminant concentrations. The 1994 monitoring was also designed to identify emerging ground-water quality problems. The information obtained is used to verify compliance with applicable environmental regulations and to evaluate remedial actions. Data from other monitoring and characterization programs were incorporated to provide an integrated assessment of Site ground-water quality. Additional characterization of the Site`s geologic setting and hydrology was performed to support the interpretation of contaminant distributions. Numerical modeling of sitewide ground-water flow also supported the overall project goals. Water-level monitoring was performed to evaluate ground-water flow directions, to track changes in water levels, and to relate such changes to changes in site disposal practices. Water levels over most of the Hanford Site continued to decline between June 1993 and June 1994. These declines are part of the continued response to the cessation of discharge to U Pond and other disposal facilities. The low permeability in this area which enhanced mounding of waste-water discharge has also slowed the response to the reduction of disposal.

Dresel, P.E.; Thorne, P.D.; Luttrell, S.P. [and others

1995-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Development and Testing of a Groundwater Management Model for the Faultless Underground Nuclear Test, Central Nevada Test Area  

DOE Green Energy (OSTI)

This document describes the development and application of a user-friendly and efficient groundwater management model of the Central Nevada Test Area (CNTA) and surrounding areas that will allow the U.S. Department of Energy and state personnel to evaluate the impact of future proposed scenarios. The management model consists of a simple hydrologic model within an interactive groundwater management framework. This framework is based on an object user interface that was developed by the U.S. Geological Survey and has been used by the Desert Research Institute researchers and others to couple disparate environmental resource models, manage the necessary temporal and spatial data, and evaluate model results for management decision making. This framework was modified and applied to the CNTA and surrounding Hot Creek Valley. The utility of the management model was demonstrated through the application of hypothetical future scenarios including mineral mining, regional expansion of agriculture, geothermal energy production, and export of water to large urban areas outside the region. While the results from some of the scenarios indicated potential impacts to the region near CNTA and others did not, together they demonstrate the usefulness of the management tool for managers who need to evaluate the impact proposed changes in groundwater use in or near CNTA may have on radionuclide migration.

Douglas P. Boyle; Gregg Lamorey; Scott Bassett; Greg Pohll; Jenny Chapman

2006-01-25T23:59:59.000Z

142

DYNAMIC MODELING STRATEGY FOR FLOW REGIME TRANSITION IN GAS-LIQUID TWO-PHASE FLOWS  

SciTech Connect

In modeling gas-liquid two-phase flows, the concept of flow regime has been used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are often flow regime dependent. Currently, the determination of the flow regimes is primarily based on flow regime maps or transition criteria, which are developed for steady-state, fully-developed flows and widely applied in nuclear reactor system safety analysis codes, such as RELAP5. As two-phase flows are observed to be dynamic in nature (fully-developed two-phase flows generally do not exist in real applications), it is of importance to model the flow regime transition dynamically for more accurate predictions of two-phase flows. The present work aims to develop a dynamic modeling strategy for determining flow regimes in gas-liquid two-phase flows through the introduction of interfacial area transport equations (IATEs) within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation and destruction of the interfacial area, such as the fluid particle (bubble or liquid droplet) disintegration, boiling and evaporation; and fluid particle coalescence and condensation, respectively. For the flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shape (which are correlated), namely small bubbles and large bubbles. A preliminary approach to dynamically identifying the flow regimes is provided, in which discriminators are based on the predicted information, such as the void fraction and interfacial area concentration of small bubble and large bubble groups. This method is expected to be applied to computer codes to improve their predictive capabilities of gas-liquid two-phase flows, in particular for the applications in which flow regime transition occurs.

X. Wang; X. Sun; H. Zhao

2011-09-01T23:59:59.000Z

143

Systematic Method for Evaluating Extraction and Injection Flow Rates for 100-KR-4 and 100-HR-3 Groundwater Operable Unit Pump-and-Treat Interim Actions for Hydraulic Containment  

Science Conference Proceedings (OSTI)

This document describes a systematic method to develop flow rate recommendations for Pump-and-Treat (P&T) extraction and injection wells in 100-KR-4 and 100-HR-3 Groundwater Operable Units (OU) of the Hanford Site. Flow rate recommendations are developed as part of ongoing performance monitoring and remedy optimization of the P&T interim actions to develop hydraulic contairnnent of the dissolved chromium plume in groundwater and protect the Columbia River from further discharges of groundwater from inland. This document details the methodology and data required to infer the influence of individual wells near the shoreline on hydraulic containment and river protection and develop flow rate recommendations to improve system performance and mitigate potential shortcomings of the system configuration in place.

Spiliotopoulos, Alexandros A.

2013-03-20T23:59:59.000Z

144

Groundwater Fate and Transport Modeling for Texarkana Wood Preserving Company Superfund Site, Texarkana, Texas  

SciTech Connect

Fate and transport model results are presented for the Texarkana Wood Preserving Company (TWPC)superfund site. The conceptual model assumes two sources of contamination, specifically, the areas around the old and new process areas. Recent data show the presence of non-aqueous phase liquids (NAPL) in the aquifer that are also sources of dissolved contamination in the aquifer. A flow model was constructed and calibrated against measured hydraulic heads at permanent monitoring wells. Good matches were obtained between model simulated heads and most measured heads. An unexplained exception occurs at monitoring well MW-13 down gradient of the site beyond the measured contaminant plume where the model predicts heads that are more than 2 ft. lower than reported field measurements. Adjusting hydraulic parameters in the model could not account for this anomaly and still preserve the head matches at other wells. There is likely a moderate deficiency in the conceptual model or perhaps a data error. Other information such as substantial amounts of infiltrating surface water in the area or a correction in surveyed elevation would improve the flow model. A particle tracking model calculated a travel time from the new process area to the Day’s Creek discharge location on the order of 40 years. Travel times from the old process area to Day’s Creek were calculated to be on the order of 80 years. While these calculations are subject to some uncertainty, travel times of decades are indicated.

Arnett, Ronald Chester

1999-08-01T23:59:59.000Z

145

A Baroclinic Model of turbulent dusty flows  

SciTech Connect

The problem considered here is the numerical simulation of the turbulent dusty flow induced by explosions over soil surfaces. Some of the unresolved issues are: (1) how much dust is scoured from such surfaces; (2) where does the dust go in the boundary layer; (3) what is the dusty boundary layer height versus time; (4) what are the dusty boundary layer profiles; (5) how much of the dust mass becomes entrained into the dust stem; and (6) where does the dust go in the buoyant cloud? The author proposes a Baroclinic Model for flows with large density variations that actually calculates the turbulent mixing and transport of dust on an adaptive grid. The model is based on the following idealizations: (1) a loose dust bed; (2) an instantaneous shock fluidization of the dust layer; (3) the dust and air are in local equilibrium (so air viscosity enforces the no-slip condition); (4) the dust-air mixture is treated as a continuum dense fluid with zero viscosity; and (5) the turbulent mixing is dominated by baroclinically-generated vorticity. These assumptions lead to an inviscid set of conservation laws for the mixture, which are solved by means of a high-order Godunov algorithm for gasdynamics. Adaptive Mesh Refinement (AMR) is used to capture the turbulent mixing processes on the grid. One of the unique characteristics of these flows is that mixing occurs because vorticity is produced by an inviscid, baroclinic mechanism. A number of examples are presented to illustrate these baroclinic effects including shock interactions with dense-gas layers and dust beds, and dusty wall jets of airblast precursors. The conclusion of these studies is that dusty boundary layers grow because of mass entrainment from the fluidized bed (and not because of viscous wall drag) as proven by the Mass Integral Equation.

Kuhl, A.L.

1992-04-01T23:59:59.000Z

146

Lisburne Formation fracture characterization and flow modeling  

E-Print Network (OSTI)

Evaluation of fractured reservoirs for fluid flow and optimal well placement is often very complicated. In general, fractures enhance permeability and increase access to matrix surface, but their random aspects create difficulties for analysis and performance prediction. Each reservoir has unique aspects which require individual assessment. This study examined fracture properties in a part of the Carboniferous Lisburne Formation. Field study of outcrops yielded information on two sets of large-scale fractures (NNW and ENE orientations) from the lower Wahoo Limestone in the eastern Sadlerochit Mountains. Several statistical methods were used on these data to find appropriate models describing the megafracture properties. For NNW fracture height and ENE fracture spacing, the gamma model appears to adequately describe the distribution. NNW fracture spacing and ENE fracture height are lognormally distributed. Results of the statistical analyses were used as input for fracture set generation and modeling using "FracMan". Modeling different borehole orientations in the fractured domain revealed that horizontal wells with 60? azimuth have an optimal trajectory, resulting in the maximum number and area of fracture connections. The orientation maximizing the number of fracture connections did not necessarily give the maximum area. Conductivity analysis showed that the fracture network is weakly anisotropic and above the percolation threshold. The fracture conductance is strongly dependent on the NNW fracture set; larger fractures influence fluid flow more than smaller fractures. Fracture strike and dip variability increased the system interconnectivity, but did not affect the optimal wellbore orientation. Incorporating ENE fracture termination against the NNW fractures decreased the system conductance and shifted the optimal wellbore trajectory towards the direction perpendicular to the NNW set. Reservoir engineering implications of this study include: guidelines for optimal wellbore orientations, the relative placement of injectors and producers along the bisectors between the two fracture sets, and the importance of including fracture terminations. Further work should investigate the influence of variations in fracture aperture and transmissivities, and drainage area, and extend the analysis to additional units of the Lisburne Group.

Karpov, Alexandre Valerievich

2001-01-01T23:59:59.000Z

147

Simulating groundwater transport process using a vertical heterogeneity model: a case study  

Science Conference Proceedings (OSTI)

It is important to simulate a groundwater transport process, e.g., pollutant migration, through the vadose zone and subsequent mixing within the saturated zone to assess potential impacts of contaminants in the subsurface in preliminary stages. It is ...

Samuel S. Lee; Hoh Peter In

2004-10-01T23:59:59.000Z

148

Modeling the effects of groundwater-fed irrigation on terrestrial hydrology over the conterminous United States  

Science Conference Proceedings (OSTI)

Human alteration of the land surface hydrologic cycle is substantial. Recent studies suggest that local water management practices including groundwater pumping and irrigation could significantly alter the quantity and distribution of water in the ...

Guoyong Leng; Maoyi Huang; Qiuhong Tang; Huilin Gao; L. Ruby Leung

149

Network flow model for multi-energy systems  

Science Conference Proceedings (OSTI)

This paper describes a novel approach to model networks with multiple energy carrier. The proposed nodal matrix establishes a link between an optimization of enclosed areas and their interconnections via networks. In the envisioned network flow model ... Keywords: energy conversion, energy hubs, grids, line losses, network flow, optimal power flow

Matthias Schulze; Goran Gašparovi?

2010-02-01T23:59:59.000Z

150

A macroscopic collisional model for debris-flows simulation  

Science Conference Proceedings (OSTI)

SCIDDICA S"4"c is the latest hexagonal release of a family of Cellular Automata models for the simulation of flow-type landslides. It is able to simulate the erosion of the regolith along the flow path, besides branching and re-joining events of the ... Keywords: Calibration, Cellular automata, Debris flows, Genetic algorithms, Modelling, Parallel processing, Sarno, Sensitivity analysis, Simulation

Donato D'Ambrosio; Giulio Iovine; William Spataro; Hideaki Miyamoto

2007-10-01T23:59:59.000Z

151

Title: Monitoring of Groundwater and Surfacewater Interactions on the Walla Walla River, Oregon for the Purpose of Restoring In-Stream flows for ESA Listed Fish Habitat Abstract  

E-Print Network (OSTI)

In an effort to restore summer flows in the Walla Walla River to provide passage and habitat for ESA (endangered species act) listed bull and steelhead trout irrigation districts left 13 cubic-feet-per-second (c.f.s) (0.37 m 3 /s) in the main channel during irrigation season (May-November) for the first time in over 100 years in 2000. However, the water percolated from the surface within a short distance of the bypass area. Agreement flows for 2001 and 2002 were 18 c.f.s. (0.51 m 3 /s), and 25 c.f.s. (0.71 m 3 /s) respectively, with an average of 28.5 c.f.s. (0.81 m 3 /s) and 32.7 c.f.s (0.93 m 3 /s) actually bypassed in 2001 and 2002 respectively. In 2001 the average loss was 15.1 c.f.s. (0.43 m 3 /s), in 2002 the average loss was 22.3 c.f.s. (0.63 m 3 /s). The ability of the mainstem to carry flow is critical to restoring fish habitat and passage. Two methods were used in conjunction to understand the interactions that occur between the Walla Walla River and the underlying alluvial aquifer. The first method was chemical signature work using naturally occurring anions in both the surface water and groundwater. Groundwater has relatively high concentrations of anions such as chloride and sulfate, compared to surface water. This allows for the use of a

John S. Selker

2003-01-01T23:59:59.000Z

152

A Study of Barotropic Model Flows: Intermittency, Waves and Predictability  

Science Conference Proceedings (OSTI)

The régime flows corresponding to the barotropic nondivergent equation with forcing, drag and subgrid-scale dissipation are studied using spectral model on the plane and on the sphere. The flow régimes obtained exhibit clear evidence of the ...

C. Basdevant; B. Legras; R. Sadourny; M. Béland

1981-11-01T23:59:59.000Z

153

Modeling of Hydraulically Controlled Exchange Flow in the Bosphorus Strait  

Science Conference Proceedings (OSTI)

Recent hydrographic observations obtained in the Bosphorus Strait illustrate several features of the flow that may be related with the internal hydraulics. A two-layer numerical model indicates that the two-way exchange flow may indeed be subject ...

Temel Oguz; Emin Özsoy; Mohammed A. Latif; Halil I. Sur; Ümit Ünlüata

1990-07-01T23:59:59.000Z

154

Modeling Flows Around Merging Black Hole Binaries  

E-Print Network (OSTI)

Coalescing massive black hole binaries are produced by the mergers of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne LISA. In cases where the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a step towards solving this problem by mapping the flow of pressureless matter in the dynamic, 3-D general relativistic spacetime around the merging black holes. We find qualitative differences in collision and outflow speeds, including a signature of the merger when the net angular momentum of the matter is low, between the results from single and binary black holes, and between nonrotating and rotating holes in binaries. If future magnetohydrodynamic results confirm ...

van Meter, James R; Miller, M Coleman; Reynolds, Christopher S; Centrella, Joan M; Baker, John G; Boggs, William D; Kelly, Bernard J; McWilliams, Sean T

2009-01-01T23:59:59.000Z

155

Fluid Flow Model Development for Representative Geologic Media | Department  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Fluid Flow Model Development for Representative Geologic Media Fluid Flow Model Development for Representative Geologic Media Fluid Flow Model Development for Representative Geologic Media Clay and granitic geologic rock units are potential host media for future repositories for used nuclear fuel and high level waste. This report addresses the representation of flow in these two media within numerical process models. Discrete fracture network (DFNs) models are an approach to representing flow in fractured granite that explicitly represents the geometry and flow properties of individual fractures. New DFN generation and computational grid generation methods have been developed and tested. Mesh generation and the generation of flow streamlines within the DFN are also included. Traditional form of Darcy's law is not adequate

156

EVALUATION OF TEMPORAL VARIATIONS IN HYDRAULIC CAPTURE DUE TO CHANGING FLOW PATTERNS USING MAPPING AND MODELING TECHNIQUES  

SciTech Connect

Robust performance evaluation represents one of the most challenging aspects of groundwater pump-and-treat (P&T) remedy implementation. In most cases, the primary goal of the P&T system is hydraulic containment, and ultimately recovery, of contaminants to protect downgradient receptors. Estimating the extent of hydraulic containment is particularly challenging under changing flow patterns due to variable pumping, boundaries and/or other conditions. We present a systematic approach to estimate hydraulic containment using multiple lines of evidence based on (a) water-level mapping and (b) groundwater modeling. Capture Frequency Maps (CFMs) are developed by particle tracking on water-level maps developed for each available water level data set using universal kriging. In a similar manner, Capture Efficiency Maps (CEMs) are developed by particle tracking on water-levels calculated using a transient groundwater flow model: tracking is undertaken independently for each stress period using a very low effective porosity, depicting the 'instantaneous' fate of each particle each stress period. Although conceptually similar, the two methods differ in their underlying assumptions and their limitations: their use together identifies areas where containment may be reliable (i.e., where the methods are in agreement) and where containment is uncertain (typically, where the methods disagree). A field-scale example is presented to illustrate these concepts.

SPILIOTOPOULOS AA; SWANSON LC; SHANNON R; TONKIN MJ

2011-04-07T23:59:59.000Z

157

Binary fish passage models for uniform and nonuniform flows  

Science Conference Proceedings (OSTI)

Binary fish passage models are considered by many fisheries managers to be the best 21 available practice for culvert inventory assessments and for fishway and barrier design. 22 Misunderstandings between different binary passage modeling approaches often arise, 23 however, due to differences in terminology, application and presentation. In this paper 24 one-dimensional binary fish passage models are reviewed and refined to clarify their 25 origins and applications. For uniform flow, a simple exhaustion-threshold (ET) model 26 equation is derived that predicts the flow speed threshold in a fishway or velocity barrier 27 that causes exhaustion at a given maximum distance of ascent. Flow speeds at or above 28 the threshold predict failure to pass (exclusion). Flow speeds below the threshold predict 29 passage. The binary ET model is therefore intuitive and easily applied to predict passage 30 or exclusion. It is also shown to be consistent with the distance-maximizing model. The 31 ET model s limitation to uniform flow is addressed by deriving a passage model that 32 accounts for nonuniform flow conditions more commonly found in the field, including 33 backwater profiles and drawdown curves. Comparison of these models with 34 experimental observations of volitional passage for Gambusia affinis in uniform and 35 nonuniform flows indicates reasonable prediction of binary outcomes (passage or 36 exclusion) if the flow speed is not near the threshold flow velocity. More research is 37 needed on fish behavior, passage strategies under nonuniform flow regimes and 38 stochastic methods that account for individual differences in swimming performance at or 39 near the threshold flow speed. Future experiments should track and measure ground 40 speeds of ascending fish to test nonuniform flow passage strategies and to improve model 41 predictions. Stochastic models, such as Monte-Carlo techniques, that account for 42 different passage performance among individuals and allow prediction of the percentage 43 of fish passing would be particularly useful near flow speed thresholds where binary 44 passage models are clearly limited.

Neary, Vincent S [ORNL

2011-01-01T23:59:59.000Z

158

Hanford Site groundwater monitoring for fiscal year 1996  

Science Conference Proceedings (OSTI)

This report presents the results of groundwater and vadose-zone monitoring for fiscal year (FY) 1996 on the Hanford Site, Washington. Hanford Site operations from 1943 onward produced large quantities of radiological and chemical waste that affected groundwater quality on the site. Characterization and monitoring of the vadose zone during FY 1996 comprised primarily spectral gamma logging, soil-gas monitoring, and electrical resistivity tomography. Water-level monitoring was performed to evaluate groundwater-flow directions, to track changes in water levels, and to relate such changes to evolving disposal practices. Water levels over most of the Hanford Site continued to decline between June 1995 and June 1996. Groundwater chemistry was monitored to track the extent of contamination, to note trends, and to identify emerging groundwater-quality problems. The most widespread radiological contaminant plumes were tritium and iodine-129. Smaller plumes of strontium-90, technetium-99, and plutonium also were present at levels above the U.S. Environmental Protection Agency or State of Washington interim drinking water standards. Uranium concentrations greater than the proposed drinking water standard were also observed. Nitrate, fluoride, chromium, carbon tetrachloride, chloroform, trichloroethylene, and cis-1,2-dichlomethylene were present in groundwater samples at levels above their U.S. Environmental Protection Agency or State of Washington maximum contaminant levels. The nitrate plume is the most extensive. Three-dimensional, numerical, groundwater models were applied to the Hanford Site to predict contaminant-flow paths and the impact of operational changes on site groundwater conditions. Other models were applied to assess the performance of three separate pump-and-treat systems.

Hartman, M.J.; Dresel, P.E.; Borghese, J.V. [eds.] [and others] [eds.; and others

1997-02-01T23:59:59.000Z

159

Flow in geothermal wells: Part III. Calculation model for self-flowing well  

DOE Green Energy (OSTI)

The theoretical model described predicts the temperature, pressure, dynamic dryness fraction, and void fraction along the vertical channel of two-phase flow. The existing data from operating wells indicate good agreement with the model. (MHR)

Bilicki, Z.; Kestin, J.; Michaelides, E.E.

1981-06-01T23:59:59.000Z

160

Modeling Flows Around Merging Black Hole Binaries  

E-Print Network (OSTI)

Coalescing massive black hole binaries are produced by the mergers of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne LISA. In cases where the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a step towards solving this problem by mapping the flow of pressureless matter in the dynamic, 3-D general relativistic spacetime around the merging black holes. We find qualitative differences in collision and outflow speeds, including a signature of the merger when the net angular momentum of the matter is low, between the results from single and binary black holes, and between nonrotating and rotating holes in binaries. If future magnetohydrodynamic results confirm these differences, it may allow assessment of the properties of the binaries as well as yielding an identifiable electromagnetic counterpart to the attendant gravitational wave signal.

James R. van Meter; John H. Wise; M. Coleman Miller; Christopher S. Reynolds; Joan M. Centrella; John G. Baker; William D. Boggs; Bernard J. Kelly; Sean T. McWilliams

2009-07-31T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Raft River monitor well potentiometric head responses and water quality as related to the conceptual ground-water flow system  

DOE Green Energy (OSTI)

Ground-water monitoring near the Raft River site was initiated in 1974 by the IDWR. This effort consisted of semiannual chemical sampling of 22 irrigation wells near the Raft River geothermal development area. This program yielded useful baseline chemical data; however, several problems were inherent. For example, access to water pumped from the wells is limited to the irrigation season (April through September). All the wells are not continuously pumped; thus, some wells that are sampled one season cannot be sampled the next. In addition, information on well construction, completion, and production is often unreliable or not available. These data are to be supplemented by establishing a series of monitor wells in the proposed geothermal withdrawal and injection area. These wells were to be located and designed to provide data necessary for evaluating and predicting the impact of geothermal development on the Shallow Aquifer system.

Allman, D.W.; Tullis, J.A.; Dolenc, M.R.; Thurow, T.L.; Skiba, P.A.

1982-09-01T23:59:59.000Z

162

Electrochemical Model of the Fe/V Redox Flow Battery  

Science Conference Proceedings (OSTI)

This paper presents a mathematical model for the new Fe/V redox flow battery chemistry. The model is designed to be useful for stack development and cost analysis purposes.

Stephenson, David E.; Kim, Soowhan; Chen, Feng; Thomsen, Edwin C.; Viswanathan, Vilayanur V.; Wang, Wei; Sprenkle, Vincent L.

2012-11-05T23:59:59.000Z

163

Raindrop Oscillations: Evaluation of a Potential Flow Model with Gravity  

Science Conference Proceedings (OSTI)

Potential flow oscillations about an equilibrium raindrop distortion were modeled for ellipsoidal variations driven by changes in surface and gravitational potential energy with linear dissipation of kinetic energy. The model was found to be ...

Kenneth V. Beard

1984-05-01T23:59:59.000Z

164

Synthetic benchmark for modeling flow in 3D fractured media  

Science Conference Proceedings (OSTI)

Intensity and localization of flows in fractured media have promoted the development of a large range of different modeling approaches including Discrete Fracture Networks, pipe networks and equivalent continuous media. While benchmarked usually within ... Keywords: Benchmark, Fractured media, Single-phase flow, Stochastic model

Jean-Raynald De Dreuzy; GéRaldine Pichot; Baptiste Poirriez; Jocelyne Erhel

2013-01-01T23:59:59.000Z

165

Magnetohydrodynamic Model Coupling Multiphase Flow in ...  

Science Conference Proceedings (OSTI)

Compact Filter Design for Gas Treatment Centers ... Gas-Solid Flow Applications for Powder Handling in Aluminum Smelters Processes ... Replacement of Damaged Electrical Insulators on Live Cross-Over Busbars inside a Tunnel: A ...

166

Can We Accurately Model Fluid Flow in Shale?  

NLE Websites -- All DOE Office Websites (Extended Search)

Can We Accurately Model Fluid Flow Can We Accurately Model Fluid Flow in Shale? Can We Accurately Model Fluid Flow in Shale? Print Thursday, 03 January 2013 00:00 Over 20 trillion cubic meters of natural gas are trapped in shale, but many shale oil and gas producers still use models of underground fluid flow that date back to the heyday of easy-to-tap gas and liquid crude. The source of shale oil and gas is kerogen, an organic material in the shale, but until now kerogen hasn't been incorporated in mathematical models of shale gas reservoirs. Paulo Monteiro, Chris Rycroft, and Grigory Isaakovich Barenblatt, with the Computational Research Division and the Advanced Light Source, recently modeled how pressure gradients in the boundary layer between kerogen inclusions and shale matrices affect productivity and can model reservoir longevity.

167

Multivariate statistical analyses of groundwater surrounding Forty mile wash  

SciTech Connect

Groundwater chemistry data from 211 sampling locations in the vicinity of Yucca Mountain, Nevada are analyzed using multivariate statistical methods in order to better understand groundwater chemical evolution, ascertain potential flow paths and determine hydrochemical facies. Correspondence analysis of the major ion chemistry is used to define relationships between and among major ions and sampling locations. A k-means cluster analysis is used to determine hydrochemical facies based on correspondence analysis dimensions. The derived dimensions and hydrochemical facies are presented as bi-plots and overlaid on a digital elevation model of the region giving a visual picture of potential interactions and flow paths. A distinct signature of the groundwater chemistry along the extended flow path of Fortymile Wash can be observed along with some potential interaction at possible fault lines near Highway I-95. The signature from Fortymile Wash is believed to represent the relict of water that infiltrated during past pluvial periods when the amount of runoff in the wash was significantly larger than during the current drier period. This hypothesis appears to be supported by hydrogen-2 and oxygen-18 data which indicate that younger groundwater is found in the upper part of the wash near Yucca Mountain and older groundwater is found in the lower region of the wash near Amargosa River. The range of the hydrogen-2 data corresponds to precipitation in a period of relatively cold climate and has a similar spatial signature to the oxygen-18 data. If the hypothesis that current groundwater chemistry primarily reflects past focused infiltration of surface runoff rather than regional groundwater migration is correct, then saturated zone transport from Yucca Mountain may be much slower than is currently anticipated. (authors)

Woocay, A.; Walton, J.C. [El Paso Univ. of Texas, Environmental Science and Engineering, TX (United States)

2007-07-01T23:59:59.000Z

168

Two-phase flow modeling with discrete particles  

SciTech Connect

The design of efficient heat exchangers in which the working fluid changes phase requires accurate modeling of two-phase fluid flow. The local Navier-Stokes equations form the basic continuum equations for this flow situation. However, the local instantaneous model using these equations is intractable for afl but the simplest problems. AH the practical models for two-phase flow analysis are based on equations that have been averaged over control volumes. These models average out the detailed description within the control volumes and rely on flow regime maps to determine the distribution of the two phases within a control volume. Flow regime maps depend on steady state models and probably are not correct for dynamic models. Numerical simulations of the averaged two-phase flow models are usually performed using a two-fluid Eulerian description for the two phases. Eulerian descriptions have the advantage of having simple boundary conditions, but the disadvantage of introducing numerical diffusion, i.e., sharp interfaces are not maintained as the flow develops, but are diffused. Lagrangian descriptions have the advantage of being able to track sharp interfaces without diffusion, but they have the disadvantage of requiring more complicated boundary conditions. This paper describes a numerical scheme and attendant computer program, DISCON2, for the calculation of two-phase flows that does not require the use of flow regime maps. This model is intermediate between the intractable local instantaneous and the averaged two-fluid model. This new model uses a combination of an Eulerian and a Lagrangian representation of the two phases. The dispersed particles (bubbles or drops) are modeled individually using a large representative number of particles, each with their own Lagrangian description. The continuous phases (liquid or gas) use an Eulerian description.

Mortensen, G.A. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Trapp, J.A. (Colorado Univ., Denver, CO (United States) EG and G Idaho, Inc., Idaho Falls, ID (United States))

1992-03-23T23:59:59.000Z

169

Advanced Conceptual Models for Unsaturated and Two-Phase Flow in Fractured Rock  

DOE Green Energy (OSTI)

This project was initiated in FY03. As of December 2003, we have accomplished the following: (1) We conducted a more detailed evaluation of the preliminary experiments used to develop our investigative approach. In those experiments, water was invaded at a variety of flow rates into an air-filled, two dimensional analog fracture network. Results demonstrated the critical control that fracture intersections place on two-phase flow in fracture networks. At low flows, capillary and gravitational forces combined to create a narrow pulsing flow structure that spanned the system vertically. At higher flows, viscous forces acted to remove the pulsation; however, the flow structure remained narrow. The intersections acted to impose a narrow ''slender ladder'' structure on the flowing phase that did not expand with depth, but instead remained focused. A manuscript documenting this effort has been published in Water Resources Research [Glass et al., 2003a]. (2) We initiated a collaborative relationship with a research group at Seoul National University. This group, which is led by Dr. Kang-Kun Lee is also using a combined experimental numerical approach to consider DNAPL migration in fracture networks. They are particularly interested in the influence of ambient groundwater flows, making their work complementary to ours. The first fruit of that collaboration is an article demonstrating that modification of an Invasion Percolation algorithm to include gravity and the first-order effects of viscous forces shows good agreement with physical experiments in a simplistic fracture network. Results were published in Geophysical Research Letters [Ji et al., 2003a]. (3) We carried out an extensive review of models for fracture networks. These include models developed from observations of networks on outcrops at several scales and stochastic models that are prevalent in the literature from the 1980s to very recent developments. The results of this review were included as par t of a review paper co-authored by Rajaram, which was submitted to Reviews in Geophysics [Molz et al., in press]. (4) We prepared a manuscript based on previous work that will be used to support the development of our new conceptual model(s) for transport in fractured rock. Eight experiments were conducted to evaluate the repeatability of flow under nearly identical conditions and to characterize general patterns in flow behavior. Collected data revealed that flow generally converged to a single fracture in the bottom row of blocks. Periods of pathway switching were observed to be more common than periods with steady, constant flow pathways. We noted the importance of fracture intersections for integrating uniform flow and discharging a ''fluid cascade'', where water advances rapidly to the next capillary barrier creating a stop and start advance of water through the network. The results of this simple experiment suggest that the interaction of multiple fracture intersections in a network creates flow behavior not generally recognized in popular conceptual and numerical models. A manuscript documenting this effort has been accepted for publication in Vadose Zone Journal [Wood et al., 2003]. (5) Slender transport pathways have been found in laboratory and field experiments within unsaturated fractured rock. We considered the simulation of such structures with a Modified form of Invasion Percolation (MIP). Results show that slender pathways form in fracture networks for a wide range of expected conditions, can be maintained when subsequent matrix imbibition is imposed, and may arise even in the context of primarily matrix flow due to the action of fractures as barriers to inter-matrix block transport. A manuscript documenting this effort has been submitted to Geophysical Research Letters [Glass et al., 2003b].

Rajaram, Harihar

2003-06-01T23:59:59.000Z

170

Solyndra Facts vs. Fiction: Cash Flow Modeling | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

You are here You are here Home » Solyndra Facts vs. Fiction: Cash Flow Modeling Solyndra Facts vs. Fiction: Cash Flow Modeling September 23, 2011 - 5:25pm Addthis Questions have been raised about a quote selectively pulled from an Aug. 20, 2009 email to make it look like Solyndra would run out of cash by Sept. 2011. To be clear, the analysis addressed in that email did not refer to Solyndra's corporate cash flow, but rather the cash flow for a subsidiary of Solyndra - the "Fab 2 Project Company." The cash flow models never said that Solyndra (the parent company) would run short of cash in September 2011. The email noted that the subsidiary was projected to have relatively low levels of cash in one particular month, and that the parent company would need to make up any potential shortfall.

171

ESS 2012 Peer Review - Flow Battery Modeling - Mario Martinez, SNL  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Photos placed in horizontal position with even amount of white space between photos and header Photos placed in horizontal position with even amount of white space between photos and header Flow Battery Modeling Energy Storage Systems Peer Review September 26-28, 2012 MJ Martinez (PI), J Clausen, SM Davison, HK Moffat Flow Battery Modeling Schematic of a Flow Battery PURPOSE: The flow battery modeling task seeks to improve fundamental understanding and enable high-performing, low-cost designs of flow batteries through

172

Development of a simple groundwater model for use in climate models and evaluation with Gravity Recovery and Climate Experiment data  

E-Print Network (OSTI)

and Hu, 2004; Yeh and Eltahir, 2005]. The rise and fall of the water table directly interacts with soil 7 April 2007. [1] Groundwater interacts with soil moisture through the exchanges of water between (SIMGM) by representing recharge and discharge processes of the water storage in an unconfined aquifer

Yang, Zong-Liang

173

Capillary instability in models for three-phase flow  

Science Conference Proceedings (OSTI)

Standard models for immiscible three-phase flow in porous media exhibit unusual behavior associated with loss of strict hyperbolicity. Anomalies were at one time thought to be confined to the region of nonhyperbolicity, where the purely convective form ... Keywords: capillary pressure instability, flow in porous media, nonunique Riemann solution

A. V. Azevedo; D. Marchesin; B. Plohr; K. Zumbrun

2002-09-01T23:59:59.000Z

174

Discrete-element modeling of particulate aerosol flows  

Science Conference Proceedings (OSTI)

A multiple-time step computational approach is presented for efficient discrete-element modeling of aerosol flows containing adhesive solid particles. Adhesive aerosol particulates are found in numerous dust and smoke contamination problems, including ... Keywords: Aerosols, Aggregation, Particle adhesion, Particulate flow

J. S. Marshall

2009-03-01T23:59:59.000Z

175

The Entropy Solutions for the Lighthill-Whitham-Richards Traffic Flow Model with a Discontinuous Flow-Density Relationship  

Science Conference Proceedings (OSTI)

In this paper we explicitly construct the entropy solutions for the Lighthill-Whitham-Richards (LWR) traffic flow model with a flow-density relationship which is piecewise quadratic, concave, but not continuous at the junction points where two quadratic ... Keywords: LWR model, WENO scheme, discontinuous flow-density relationship, entropy solution, traffic flow

Yadong Lu; S. C. Wong; Mengping Zhang; Chi-Wang Shu

2009-11-01T23:59:59.000Z

176

Numerical models for high beta magnetohydrodynamic flow  

Science Conference Proceedings (OSTI)

The fundamentals of numerical magnetohydrodynamics for highly conducting, high-beta plasmas are outlined. The discussions emphasize the physical properties of the flow, and how elementary concepts in numerical analysis can be applied to the construction of finite difference approximations that capture these features. The linear and nonlinear stability of explicit and implicit differencing in time is examined, the origin and effect of numerical diffusion in the calculation of convective transport is described, and a technique for maintaining solenoidality in the magnetic field is developed. Many of the points are illustrated by numerical examples. The techniques described are applicable to the time-dependent, high-beta flows normally encountered in magnetically confined plasmas, plasma switches, and space and astrophysical plasmas. 40 refs.

Brackbill, J.U.

1987-01-01T23:59:59.000Z

177

A CFD Model for Simulating Urban Flow and Dispersion  

Science Conference Proceedings (OSTI)

A three-dimensional computational fluid dynamics (CFD) model is developed to simulate urban flow and dispersion, to understand fluid dynamical processes therein, and to provide practical solutions to some emerging problems of urban air pollution. ...

Jong-Jin Baik; Jae-Jin Kim; Harindra J. S. Fernando

2003-11-01T23:59:59.000Z

178

Modeling and design of semi-solid flow batteries  

E-Print Network (OSTI)

A three-dimensional dynamic model of the recently introduced semi-solid flow battery system is developed and applied to address issues with important design and operation implications. Because of the high viscosity of ...

Brunini, Victor Eric

2012-01-01T23:59:59.000Z

179

CFD Modeling of Fluid Flow Behavior and Bath Surface Deformation ...  

Science Conference Proceedings (OSTI)

Direct Numerical Simulation of Inclusion Turbulent Deposition at Liquid ... Flow and Shrinkage Pipe Formation on Macrosegregation of Investment Cast -TiAl Alloys ... Numerical Modeling of the Interaction between a Foreign Particle an ...

180

Can We Accurately Model Fluid Flow in Shale?  

NLE Websites -- All DOE Office Websites (Extended Search)

2013 00:00 Over 20 trillion cubic meters of natural gas are trapped in shale, but many shale oil and gas producers still use models of underground fluid flow that date back to...

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

ESS 2012 Peer Review - Flow Battery Modeling - Mario Martinez...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

in horizontal position with even amount of white space between photos and header Flow Battery Modeling Energy Storage Systems Peer Review September 26-28, 2012 MJ Martinez (PI), J...

182

Hanford Site ground-water monitoring for 1993  

Science Conference Proceedings (OSTI)

This report presents the results of the Ground-Water Surveillance Project monitoring for calendar year 1993 on the Hanford Site, Washington. Hanford Site operations from 1943 onward produced large quantities of radiological and chemical waste that have impacted ground-water quality on the Site. Monitoring of water levels and ground-water chemistry is performed to track the extent of contamination and trends in contaminant concentrations. The 1993 monitoring was also designed to identify emerging ground-water quality problems. The information obtained is used to verify compliance with applicable environmental regulations and to evaluate remedial actions. Data from other monitoring and characterization programs were incorporated to provide an integrated assessment of Site ground-water quality. Additional characterization of the Site`s geologic setting and hydrology was performed to support the interpretation of contaminant distributions. Numerical modeling of sitewide ground-water flow also supported the overall project goals. Water-level monitoring was performed to evaluate ground-water flow directions, to track changes in water levels, and to relate such changes to changes in site disposal practices. Water levels over most of the Hanford Site continued to decline between June 1992 and June 1993. The greatest declines occurred in the 200-West Area. These declines are part of the continued response to the cessation of discharge to U Pond and other disposal facilities. The low permeability in this area which enhanced mounding of waste-water discharge has also slowed the response to the reduction of disposal. Water levels remained nearly constant in the vicinity of B Pond, as a result of continued disposal to the pond. Water levels measured from wells in the unconfined aquifer north and east of the Columbia River indicate that the primary source of recharge is irrigation practices.

Dresel, P.E.; Luttrell, S.P.; Evans, J.C. [and others

1994-09-01T23:59:59.000Z

183

A coupled model of fluid flow in jointed rock  

SciTech Connect

We present a fully coupled model of fluid flow in jointed rock, where the fluid flow depends on the joint openings and the joint openings depend on the fluid pressure. The joints and rock blocks are modeled discretely using the finite element method. Solutions for the fluid and rock are obtained and iteration is performed until both solutions converge. Example applications include an examination of the effects of back-pressure on flow in a geothermal reservoir and transient fluid injection into a reservoir.

Swenson, Daniel; Martineau, Rick; James, Mark; Brown, Don

1991-01-01T23:59:59.000Z

184

Efficient Algorithms for Modeling Reacting Flows  

NLE Websites -- All DOE Office Websites (Extended Search)

the development of efficient numerical algorithms that reduce the time required to model combustion phenomena are of great interest. In this talk I will present the development...

185

A stochastic index flow model of flow duration curves Attilio Castellarin  

E-Print Network (OSTI)

2004; published 10 March 2004. [1] Annual flow duration curves (AFDCs) are used increasingly because for the median AFDC, they enable one to assign return periods to individual AFDCs, and they offer opportunities for developing a generalized stochastic model of daily streamflow. Previous stochastic models of FDCs and AFDCs

Vogel, Richard M.

186

Engineering Geology 52 (1999) 231250 Mathematical modelling of groundwater flow at Sellafield, UK  

E-Print Network (OSTI)

-state, the of the quadrilaterals) are then calculated for each conservation of thermal energy can be expressed node Eq. (6). as/outflux sites and their driving energies effect of varying the hydraulic conductivity of theare separate Hotel, London. hydraulic conductivity of low permeability Black, J.H., Brightman, M.A., 1996. Conceptual

Haszeldine, Stuart

187

Nanoscale Pore Imaging and Pore Scale Fluid Flow Modeling in Chalk  

E-Print Network (OSTI)

NTRODUCTION To model multiphase flow in porous media at porein porous media - pore-network models and multiphase flow”,porous microstructures. ” International Journal of Multiphase

Tomutsa, Liviu; Silin, Dmitriy

2004-01-01T23:59:59.000Z

188

Nanometer-scale imaging and pore-scale fluid flow modeling in chalk  

E-Print Network (OSTI)

pores. To model multiphase flow in porous media at porein porous media - pore-network models and multiphase flow”,porous microstructures. ” International Journal of Multiphase

Tomutsa, Liviu; Silin, Dmitriy; Radmilovich, Velimir

2005-01-01T23:59:59.000Z

189

Particle-fluid two-phase flow modeling  

SciTech Connect

This paper describes a numerical scheme and computer program, DISCON, for the calculation of two-phase flows that does not require the use of flow regime maps. This model is intermediate between-thermal instantaneous and the averaged two-fluid model. It solves the Eulerian continuity, momentum, and energy equations for each liquid control volume, and the Lagrangian mass, momentum, energy, and position equations for each bubble. The bubbles are modeled individually using a large representative number of bubbles thus avoiding the numerical diffusion associated with Eulerian models. DISCON has been used to calculate the bubbling of air through a column of water and the subcooled boiling of water in a flow channel. The results of these calculations are presented.

Mortensen, G.A. [EG and G Idaho, Inc., Idaho Falls, ID (United States); Trapp, J.A. [Colorado Univ., Denver, CO (United States)]|[Idaho National Engineering Lab., Idaho Falls, ID (United States)

1992-09-01T23:59:59.000Z

190

Particle-fluid two-phase flow modeling  

Science Conference Proceedings (OSTI)

This paper describes a numerical scheme and computer program, DISCON, for the calculation of two-phase flows that does not require the use of flow regime maps. This model is intermediate between-thermal instantaneous and the averaged two-fluid model. It solves the Eulerian continuity, momentum, and energy equations for each liquid control volume, and the Lagrangian mass, momentum, energy, and position equations for each bubble. The bubbles are modeled individually using a large representative number of bubbles thus avoiding the numerical diffusion associated with Eulerian models. DISCON has been used to calculate the bubbling of air through a column of water and the subcooled boiling of water in a flow channel. The results of these calculations are presented.

Mortensen, G.A. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Trapp, J.A. (Colorado Univ., Denver, CO (United States) Idaho National Engineering Lab., Idaho Falls, ID (United States))

1992-01-01T23:59:59.000Z

191

Power flow management of microgrid networks using model predictive control  

Science Conference Proceedings (OSTI)

In this paper, we present a power flow management method for a network of cooperating microgrids within the context of a smart grid by formulating the problem in a model predictive control framework. In order to reliably and economically provide the ... Keywords: Microgrid, Model predictive control, Renewable energy sources, Smart grid, Storage devices

A. Hooshmand; H. A. Malki; J. Mohammadpour

2012-09-01T23:59:59.000Z

192

A Laboratory Model of Urban Street-Canyon Flows  

Science Conference Proceedings (OSTI)

A circulating water channel is constructed to examine urban street-canyon flow. In the cases of an even-notch street canyon in which model buildings on both sides of the street have equal heights, one vortex is observed in model canyons with ...

Jong-Jin Baik; Rae-Seol Park; Hye-Yeong Chun; Jae-Jin Kim

2000-09-01T23:59:59.000Z

193

Introduction Application of numerical models of ground water flow  

E-Print Network (OSTI)

Introduction Application of numerical models of ground water flow almost always involves some sort (Yeh 1986; Poeter and Hill 1997; Hill et al. 1998). Other data beside hydraulic head have been used in calibration of ground water models, including rates of ground water exchange with streams and other surface

Saiers, James

194

Field site investigation: Effect of mine seismicity on groundwater hydrology  

Science Conference Proceedings (OSTI)

The results of a field investigation on the groundwater-hydrologic effect of mining-induced earthquakes are presented in this report. The investigation was conducted at the Lucky Friday Mine, a silver-lead-zinc mine in the Coeur d`Alene Mining District of Idaho. The groundwater pressure in sections of three fracture zones beneath the water table was monitored over a 24-mo period. The fracture zones were accessed through a 360-m-long inclined borehole, drilled from the 5,700 level station of the mine. The magnitude, source location, and associated ground motions of mining-induced seismic events were also monitored during the same period, using an existing seismic instrumentation network for the mine, augmented with additional instruments installed specifically for the project by the center for Nuclear Waste Regulatory Analyses (CNWRA). More than 50 seismic events of Richter magnitude 1.0 or larger occurred during the monitoring period. Several of these events caused the groundwater pressure to increase, whereas a few caused it to decrease. Generally, the groundwater pressure increased as the magnitude of seismic event increased; for an event of a given magnitude, the groundwater pressure increased by a smaller amount as the distance of the observation point from the source of the event increased. The data was examined using regression analysis. Based on these results, it is suggested that the effect of earthquakes on groundwater flow may be better understood through mechanistic modeling. The mechanical processes and material behavior that would need to be incorporated in such a model are examined. They include a description of the effect of stress change on the permeability and water storage capacity of a fracture rock mass; transient fluid flow; and the generation and transmission of seismic waves through the rock mass.

Ofoegbu, G.I.; Hsiung, S.; Chowdhury, A.H. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses; Philip, J. [Nuclear Regulatory Commission, Washington, DC (United States)

1995-04-01T23:59:59.000Z

195

A simplified sizing and mass model for axial flow turbines  

SciTech Connect

An axial flow turbine mass model has been developed and used to study axial flow turbines for space power systems. Hydrogen, helium-xenon, hydrogen-water vapor, air, and potassium vapor working fluids have been investigated to date. The impact of construction material, inlet temperature, rotational speed, pressure ratio, and power level on turbine mass and volume has been analyzed. This paper presents the turbine model description and results of parametric studies showing general design trends characteristic of any axial flow machine. Also, a comparison of axial flow turbine designs using helium-xenon mixtures and potassium vapor working fluids, which are used in Brayton and Rankine space power systems, respectively, is presented. 9 refs., 4 figs., 2 tabs.

Hudson, S.L.

1989-01-01T23:59:59.000Z

196

Wetting and free surface flow modeling for potting and encapsulation.  

Science Conference Proceedings (OSTI)

As part of an effort to reduce costs and improve quality control in encapsulation and potting processes the Technology Initiative Project ''Defect Free Manufacturing and Assembly'' has completed a computational modeling study of flows representative of those seen in these processes. Flow solutions are obtained using a coupled, finite-element-based, numerical method based on the GOMA/ARIA suite of Sandia flow solvers. The evolution of the free surface is solved with an advanced level set algorithm. This approach incorporates novel methods for representing surface tension and wetting forces that affect the evolution of the free surface. In addition, two commercially available codes, ProCAST and MOLDFLOW, are also used on geometries representing encapsulation processes at the Kansas City Plant. Visual observations of the flow in several geometries are recorded in the laboratory and compared to the models. Wetting properties for the materials in these experiments are measured using a unique flowthrough goniometer.

Brooks, Carlton, F.; Brooks, Michael J. (Los Alamos National Laboratory, Los Alamos, NM); Graham, Alan Lyman (Los Alamos National Laboratory, Los Alamos, NM); Noble, David F. (David Frederick) (.; )); Notz, Patrick K.; Hopkins, Matthew Morgan; Castaneda, Jaime N.; Mahoney, Leo James (Kansas City Plant, Kansas City, MO); Baer, Thomas A.; Berchtold, Kathryn (Los Alamos National Laboratory, Los Alamos, NM); Adolf, Douglas Brian; Wilkes, Edward Dean; Rao, Rekha Ranjana; Givler, Richard C.; Sun, Amy Cha-Tien; Cote, Raymond O.; Mondy, Lisa Ann; Grillet, Anne Mary; Kraynik, Andrew Michael

2007-06-01T23:59:59.000Z

197

A fracture network model for water flow and solute transport  

DOE Green Energy (OSTI)

This paper summarizes code development work and sample calculations for FRACNET, a two-dimensional steady state simulator of fluid flow and solute transport in fractured porous media. The model analyzes flow and transport by generating a fracture network based on statistical characteristics of fractures obtained from well logs and other data. After a network is generated, flow and tracer transport are computed for appropriate boundary conditions and wellbore source/sink terms. In addition, for a given realization, the code can be used to indicate whether the medium can be treated as an equivalent porous medium. 18 refs., 7 figs.

Robinson, B.A.

1989-01-01T23:59:59.000Z

198

Regional Groundwater Evapotranspiration in Illinois  

Science Conference Proceedings (OSTI)

The role of shallow unconfined aquifers in supplying water for evapotranspiration (i.e., groundwater evaporation) is investigated in this paper. Recent results from regional land surface modeling have indicated that in shallow water table areas, ...

Pat J-F. Yeh; J. S. Famiglietti

2009-04-01T23:59:59.000Z

199

GIS-BASED 1-D DIFFUSIVE WAVE OVERLAND FLOW MODEL  

Science Conference Proceedings (OSTI)

This paper presents a GIS-based 1-d distributed overland flow model and summarizes an application to simulate a flood event. The model estimates infiltration using the Green-Ampt approach and routes excess rainfall using the 1-d diffusive wave approximation. The model was designed to use readily available topographic, soils, and land use/land cover data and rainfall predictions from a meteorological model. An assessment of model performance was performed for a small catchment and a large watershed, both in urban environments. Simulated runoff hydrographs were compared to observations for a selected set of validation events. Results confirmed the model provides reasonable predictions in a short period of time.

KALYANAPU, ALFRED [Los Alamos National Laboratory; MCPHERSON, TIMOTHY N. [Los Alamos National Laboratory; BURIAN, STEVEN J. [NON LANL

2007-01-17T23:59:59.000Z

200

Liquid-fluidized-bed heat exchanger flow distribution models  

DOE Green Energy (OSTI)

Allied Chemical Corporation at the Idaho National Engineering Laboratory is developing liquid-fluidized-bed shell-and-tube heat exchangers for geothermal applications. Sand fluidized by geothermal water on the shell side prevents scaling and increases heat transfer coefficients over conventional heat exchangers. Tests were conducted on two instrumented fluidized-bed heat exchanger models, constructed primarily of plexiglass, which differ in tube bundle orientation. One contains a horizontal bundle and the other a vertical tube bundle. Plexiglass construction allowed visual observation of flow patterns. The vertical model proved to have more uniform flow distribution and higher heat transfer coefficients than the horizontal model. The horizontal heat exchanger experienced piling on top of the tubes and areas of poor fluidization existed in the bed. Geometric considerations show that a horizontal design is more conducive to large flow rates than a vertical design. New design concepts for both vertical and horizontal assemblies and recommendations for further developmental work are presented.

Cole, L.T.; Allen, C.A.

1979-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Multiphase Flow Modeling of Biofuel Production Processes  

Science Conference Proceedings (OSTI)

As part of the Idaho National Laboratory's (INL's) Secure Energy Initiative, the INL is performing research in areas that are vital to ensuring clean, secure energy supplies for the future. The INL Hybrid Energy Systems Testing (HYTEST) Laboratory is being established to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence on foreign petroleum. HYTEST involves producing liquid fuels in a Hybrid Energy System (HES) by integrating carbon-based (i.e., bio-mass, oil-shale, etc.) with non-carbon based energy sources (i.e., wind energy, hydro, geothermal, nuclear, etc.). Advances in process development, control and modeling are the unifying vision for HES. This paper describes new modeling tools and methodologies to simulate advanced energy processes. Needs are emerging that require advanced computational modeling of multiphase reacting systems in the energy arena, driven by the 2007 Energy Independence and Security Act, which requires production of 36 billion gal/yr of biofuels by 2022, with 21 billion gal of this as advanced biofuels. Advanced biofuels derived from microalgal biomass have the potential to help achieve the 21 billion gal mandate, as well as reduce greenhouse gas emissions. Production of biofuels from microalgae is receiving considerable interest due to their potentially high oil yields (around 600 gal/acre). Microalgae have a high lipid content (up to 50%) and grow 10 to 100 times faster than terrestrial plants. The use of environmentally friendly alternatives to solvents and reagents commonly employed in reaction and phase separation processes is being explored. This is accomplished through the use of hydrothermal technologies, which are chemical and physical transformations in high-temperature (200-600 C), high-pressure (5-40 MPa) liquid or supercritical water. Figure 1 shows a simplified diagram of the production of biofuels from algae. Hydrothermal processing has significant advantages over other biomass processing methods with respect to separations. These 'green' alternatives employ a hybrid medium that, when operated supercritically, offers the prospect of tunable physicochemical properties. Solubility can be rapidly altered and phases partitioned selectively to precipitate or dissolve certain components by altering temperature or pressure in the near-critical region. The ability to tune the solvation properties of water in the highly compressible near-critical region facilitates partitioning of products or by-products into separate phases to separate and purify products. Since most challenges related to lipid extraction are associated with the industrial scale-up of integrated extraction systems, the new modeling capability offers the prospect of addressing previously untenable scaling issues.

D. Gaston; D. P. Guillen; J. Tester

2011-06-01T23:59:59.000Z

202

Coupled modeling of non-isothermal multiphase flow, solutetransport and reactive chemistry in porous and fractured media: 1. ModelDevelopment and Validation  

Science Conference Proceedings (OSTI)

Coupled modeling of subsurface multiphase fluid and heat flow, solute transport and chemical reactions can be used for the assessment of acid mine drainage remediation, mineral deposition, waste disposal sites, hydrothermal convection, contaminant transport, and groundwater quality. Here they present a numerical simulation model, TOUGHREACT, which considers non-isothermal multi-component chemical transport in both liquid and gas phases. A wide range of subsurface thermo-physical-chemical processes is considered. The model can be applied to one-, two- or three-dimensional porous and fractured media with physical and chemical heterogeneity. The model can accommodate any number of chemical species present in liquid, gas and solid phases. A variety of equilibrium chemical reactions is considered, such as aqueous complexation, gas dissolution/exsolution, cation exchange, and surface complexation. Mineral dissolution/precipitation can proceed either subject to local equilibrium or kinetic conditions. The coupled model employs a sequential iteration approach with reasonable computing efficiency. The development of the governing equations and numerical approach is presented along with the discussion of the model implementation and capabilities. The model is verified for a wide range of subsurface physical and chemical processes. The model is well suited for flow and reactive transport in variably saturated porous and fractured media. In the second of this two-part paper, three applications covering a variety of problems are presented to illustrate the capabilities of the model.

Xu, Tianfu; Pruess, Karsten

1998-09-01T23:59:59.000Z

203

Geothermal loan guaranty cash flow model: description and users' manual  

SciTech Connect

This is the users guide for the Geothermal Loan Guaranty Cash Flow Model (GCFM). GCFM is a Fortran code which designs and costs geothermal fields and electric power plants. It contains a financial analysis module which performs life cycle costing analysis taking into account various types of taxes, costs and financial structures. The financial module includes a discounted cash flow feature which calculates a levelized breakeven price for each run. The user's guide contains descriptions of the data requirements and instructions for using the model.

Keimig, M.A.; Rosenberg, J.I.; Entingh, D.J.

1980-11-01T23:59:59.000Z

204

An Integrated Modeling Analysis of Unsaturated Flow Patterns in Fractured Rock  

E-Print Network (OSTI)

study, heat flow simulations use a 3-D thermal model grid (model grid, which is used for gas flow and ambient heat-flowgrid showing a smaller model domain, used for modeling gas and heat

Wu, Yu-Shu; Lu, Guoping; Zhang, Keni; Pan, Lehua; Bodvarsson, Gudmundur S.

2008-01-01T23:59:59.000Z

205

Measuring and Modeling Flow in Welded Fractured Tuffs  

SciTech Connect

We have carried out a series of in situ liquid-release experiments in conjunction with a numerical modeling study to examine the effect of the rock matrix on liquid flow and transport occurring primarily through the fracture network. Field experiments were conducted in the highly fractured Topopah Spring welded tuff at a site accessed from the Exploratory Studies Facility (ESFS), an underground laboratory in the unsaturated zone at Yucca Mountain, Nevada. During the experiment, wetting-front movement, flow-field evolution, and drainage of fracture flow paths were evaluated. Modeling was used to aid in experimental design, predict experimental results, and study the physical processes accompanying liquid flow through unsaturated fractured welded tuff. Field experiments and modeling suggest that it may not be sufficient to conceptualize the fractured tuff as consisting of a single network of high-permeability fractures embedded in a low-permeability matrix. The need to include a secondary fracture network is demonstrated by comparison to the liquid flow observed in the field.

R. Salve; C. Doughty; J.S. Wang

2001-10-03T23:59:59.000Z

206

Development, Verification, and Validation of Multiphase Models for Polydisperse Flows  

Science Conference Proceedings (OSTI)

This report describes in detail the technical findings of the DOE Award entitled 'Development, Verification, and Validation of Multiphase Models for Polydisperse Flows.' The focus was on high-velocity, gas-solid flows with a range of particle sizes. A complete mathematical model was developed based on first principles and incorporated into MFIX. The solid-phase description took two forms: the Kinetic Theory of Granular Flows (KTGF) and Discrete Quadrature Method of Moments (DQMOM). The gas-solid drag law for polydisperse flows was developed over a range of flow conditions using Discrete Numerical Simulations (DNS). These models were verified via examination of a range of limiting cases and comparison with Discrete Element Method (DEM) data. Validation took the form of comparison with both DEM and experimental data. Experiments were conducted in three separate circulating fluidized beds (CFB's), with emphasis on the riser section. Measurements included bulk quantities like pressure drop and elutriation, as well as axial and radial measurements of bubble characteristics, cluster characteristics, solids flux, and differential pressure drops (axial only). Monodisperse systems were compared to their binary and continuous particle size distribution (PSD) counterparts. The continuous distributions examined included Gaussian, lognormal, and NETL-provided data for a coal gasifier.

Christine Hrenya; Ray Cocco; Rodney Fox; Shankar Subramaniam; Sankaran Sundaresan

2011-12-31T23:59:59.000Z

207

A model for multiphase flows through poroelastic media  

Science Conference Proceedings (OSTI)

A continuum model for multiphase fluid mixture flows through poroelastic media is presented. The basic conservation laws developed via a volume averaging technique are considered. Effects of phasic equilibrated forces are included in the model. Based on the thermodynamics of the multiphase mixture flows, appropriate constitutive equations are formulated. The entropy inequality is exploited, and the method of Lagrangian multiplier is used along with the phasic conservation laws to derive the constitutive equations for the phasic stress tensors, equilibrated stress vectors, and the interactions terms. The special cases of wave propagation in poroelastic media saturated with multiphase fluids, and multiphase flows through porous media, are studied. It is shown that the present theory leads to the extended Darcy’s law and contains, as a special case, Biot’s theory of saturated poroelastic media.

Ahmadi, Goodarz; Mazaheri, Ali Reza; Smith, D.H

2003-01-01T23:59:59.000Z

208

Modeling of fluid and heat flow in fractured geothermal reservoirs  

DOE Green Energy (OSTI)

In most geothermal reservoirs large-scale permeability is dominated by fractures, while most of the heat and fluid reserves are stored in the rock matrix. Early-time fluid production comes mostly from the readily accessible fracture volume, while reservoir behavior at later time depends upon the ease with which fluid and heat can be transferred from the rock matrix to the fractures. Methods for modeling flow in fractured porous media must be able to deal with this matrix-fracture exchange, the so-called interporosity flow. This paper reviews recent work at Lawrence Berkeley Laboratory on numerical modeling of nonisothermal multiphase flow in fractured porous media. We also give a brief summary of simulation applications to problems in geothermal production and reinjection. 29 refs., 1 fig.

Pruess, K.

1988-08-01T23:59:59.000Z

209

A viscosity counteracting approach in the lattice Boltzmann BGK model for low viscosity flow: Preliminary verification  

Science Conference Proceedings (OSTI)

Due to numerical instability, the lattice Boltzmann model (LBM) with the Bhatnagar-Gross-Krook (BGK) collision operator has some limitations in the simulation of low viscosity flows. In this paper, we propose a viscosity counteracting approach for simulating ... Keywords: Couette flow, Lattice Boltzmann BGK model, Lid-driven cavity flow, Poiseuille flow, Taylor-Green vortex flow, Verification, Viscosity counteracting

Yongguang Cheng; Hui Zhang

2011-06-01T23:59:59.000Z

210

Variably Saturated Flow and Multicomponent Biogeochemical Reactive Transport Modeling of a Uranium Bioremediation Field Experiment  

Science Conference Proceedings (OSTI)

Field experiments at a former uranium mill tailings site have identified the potential for stimulating indigenous bacteria to catalyze the conversion of aqueous uranium in the +6 oxidation state to immobile solid-associated uranium in the +4 oxidation state. This effectively removes uranium from solution resulting in groundwater concentrations below actionable standards. Three-dimensional, coupled variably-saturated flow and biogeochemical reactive transport modeling of a 2008 in situ uranium bioremediation field experiment is used to better understand the interplay of transport rates and biogeochemical reaction rates that determine the location and magnitude of key reaction products. A comprehensive reaction network, developed largely through previous 1-D modeling studies, was used to simulate the impacts on uranium behavior of pulsed acetate amendment, seasonal water table variation, spatially-variable physical (hydraulic conductivity, porosity) and geochemical (reactive surface area) material properties. A principal challenge is the mechanistic representation of biologically-mediated terminal electron acceptor process (TEAP) reactions whose products significantly alter geochemical controls on uranium mobility through increases in pH, alkalinity, exchangeable cations, and highly reactive reduction products. In general, these simulations of the 2008 Big Rusty acetate biostimulation field experiment in Rifle, Colorado confirmed previously identified behaviors including (1) initial dominance by iron reducing bacteria that concomitantly reduce aqueous U(VI), (2) sulfate reducing bacteria that become dominant after {approx}30 days and outcompete iron reducers for the acetate electron donor, (3) continuing iron-reducer activity and U(VI) bioreduction during dominantly sulfate reducing conditions, and (4) lower apparent U(VI) removal from groundwater during dominantly sulfate reducing conditions. New knowledge on simultaneously active metal and sulfate reducers has been incorporated into the modeling. In this case, an initially small population of slow growing sulfate reducers is active from the initiation of biostimulation. Three-dimensional, variably saturated flow modeling was used to address impacts of a falling water table during acetate injection. These impacts included a significant reduction in aquifer saturated thickness and isolation of residual reactants and products, as well as unmitigated uranium, in the newly unsaturated vadose zone. High permeability sandy gravel structures resulted in locally high flow rates in the vicinity of injection wells that increased acetate dilution. In downgradient locations, these structures created preferential flow paths for acetate delivery that enhanced local zones of TEAP reactivity and subsidiary reactions. Conversely, smaller transport rates associated with the lower permeability lithofacies (e.g., fine) and vadose zone were shown to limit acetate access and reaction. Once accessed by acetate, however, these same zones limited subsequent acetate dilution and provided longer residence times that resulted in higher concentrations of TEAP products when terminal electron donors and acceptors were not limiting. Finally, facies-based porosity and reactive surface area variations were shown to affect aqueous uranium concentration distributions; however, the ranges were sufficiently small to preserve general trends. Large computer memory and high computational performance were required to simulate the detailed coupled process models for multiple biogeochemical components in highly resolved heterogeneous materials for the 110-day field experiment and 50 days of post-biostimulation behavior. In this case, a highly-scalable subsurface simulator operating on 128 processor cores for 12 hours was used to simulate each realization. An equivalent simulation without parallel processing would have taken 60 days, assuming sufficient memory was available.

Yabusaki, Steven B.; Fang, Yilin; Williams, Kenneth H.; Murray, Christopher J.; Ward, Anderson L.; Dayvault, Richard; Waichler, Scott R.; Newcomer, Darrell R.; Spane, Frank A.; Long, Philip E.

2011-11-01T23:59:59.000Z

211

Continental-Scale River Flow in Climate Models  

Science Conference Proceedings (OSTI)

The hydrologic cycle is a major part of the global climate system. There is an atmospheric flux of water from the ocean surface to the continents. The cycle is closed by return flow in rivers. In this paper a river routing model is developed to ...

James R. Miller; Gary L. Russell; Guilherme Caliri

1994-06-01T23:59:59.000Z

212

Sleep scheduling for wireless sensor networks via network flow model  

Science Conference Proceedings (OSTI)

The pervasiveness and operational autonomy of mesh-based wireless sensor networks (WSNs) make them an ideal candidate in offering sustained monitoring functions at reasonable cost over a wide area. There has been a general consensus within the research ... Keywords: Cross-layer design, Integer linear programming, Network flow model, Sleep scheduling, Wireless sensor networks

Rick W. Ha; Pin-Han Ho; X. Sherman Shen; Junshan Zhang

2006-08-01T23:59:59.000Z

213

Incorporating Anthropogenic Water Regulation Modules into a Land Surface Model  

Science Conference Proceedings (OSTI)

Anthropogenic activities have been significantly perturbing global freshwater flows and groundwater reserves. Despite numerous advances in the development of land surface models (LSMs) and global terrestrial hydrological models (GHMs), relatively ...

Yadu Pokhrel; Naota Hanasaki; Sujan Koirala; Jaeil Cho; Pat J.-F. Yeh; Hyungjun Kim; Shinjiro Kanae; Taikan Oki

2012-02-01T23:59:59.000Z

214

New shear-free relativistic models with heat flow  

E-Print Network (OSTI)

We study shear-free spherically symmetric relativistic models with heat flow. Our analysis is based on Lie's theory of extended groups applied to the governing field equations. In particular, we generate a five-parameter family of transformations which enables us to map existing solutions to new solutions. All known solutions of Einstein equations with heat flow can therefore produce infinite families of new solutions. In addition, we provide two new classes of solutions utilising the Lie infinitesimal generators. These solutions generate an infinite class of solutions given any one of the two unknown metric functions.

A. M. Msomi; K. S. Govinder; S. D. Maharaj

2012-12-29T23:59:59.000Z

215

Parameter estimation from flowing fluid temperature logging data in unsaturated fractured rock using multiphase inverse modeling  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media, Soc.fluid and heat flows of multiphase, multicomponent fluid mixtures in porous and fractured media.

Mukhopadhyay, S.

2009-01-01T23:59:59.000Z

216

Analyzing flow patterns in unsaturated fractured rock of Yucca Mountain using an integrated modeling approach  

E-Print Network (OSTI)

heat flow simulations use the 3-D thermal model grid (Figuremodel grid, which is used for gas flow and ambient heat flowgrid showing a smaller model domain, used for modeling gas and heat

Wu, Yu-Shu; Lu, Guoping; Zhang, Keni; Pan, Lehua; Bodvarsson, Gudmundur S.

2008-01-01T23:59:59.000Z

217

Laboratory–Numerical Model Comparisons of Flow over a Coastal Canyon  

Science Conference Proceedings (OSTI)

Different modeling approaches are applied to the same geophysical flow in order to assess the ability of laboratory models to provide useful benchmarks in the development of oceanic numerical models. The test case considered here—that of the flow ...

Nicolas Pérenne; Dale B. Haidvogel; Don L. Boyer

2001-02-01T23:59:59.000Z

218

Reactive transport model for the ambient unsaturated hydrogeochemical system at Yucca mountain, Nevada  

Science Conference Proceedings (OSTI)

To assist a technical review of a potential application for a geologic repository, a reactive transport model is presented for the ambient hydrogeochemical system at Yucca Mountain (YM). The model simulates two-phase, nonisothermal, advective and diffusive ... Keywords: Yucca mountain, geochemistry, groundwater chemistry, groundwater flow and transport, hydrology, reactive transport model, unsaturated zone

Lauren Browning; William M. Murphy; Chandrika Manepally; Randall Fedors

2003-04-01T23:59:59.000Z

219

FRAMES-2.0 Software System: Linking to the Groundwater Modeling System (GMS) RT3D and MT3DMS Models  

SciTech Connect

Linkages to the Groundwater Modeling System have been developed at Pacific Northwest National Laboratory to enable the Nuclear Regulatory Commission (NRC) to more realistically assess the risk to the public of radioactive contaminants at NRC-licensed sites. Common software tools presently in use are limited in that they cannot assess contaminant migration through complex natural environments. The purpose of this initiative is to provide NRC with a licensing safety-analysis tool with sufficient power, flexibility, and utility that it can serve as the primary software platform for analyzing the hazards associated with licensing actions at those “complex” sites at which the traditional tools are inappropriate. As a tool designed to realistically approximate prospective doses to the public, this initiative addresses NRC’s safety-performance goal by confirming that licensing actions do not result in undue risk to the public.

Whelan, Gene; Castleton, Karl J.; Pelton, Mitch A.

2007-08-08T23:59:59.000Z

220

2.853 Manufacturing Systems I: Analytical Methods and Flow Models, Fall 2002  

E-Print Network (OSTI)

Provides ways to conceptualize and analyze manufacturing systems and supply chains in terms of material flow, information flow, capacities, and flow times. Fundamental building blocks: Inventory and Queuing Models, Forecasting ...

Gershwin, S. B.

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221

Analytical solution for two-phase flow in a wellbore using the drift-flux model  

E-Print Network (OSTI)

Wellbore flow model for carbon dioxide and brine, EnergyReservoir Flow of Carbon Dioxide and Water. LBNL-4291E. [14]non-isothermal flow of carbon dioxide in wellbores. In: SPE

Pan, L.

2013-01-01T23:59:59.000Z

222

Numerical Simulation of Groundwater Withdrawal within the Mercury Valley Administrative Groundwater Basin, Nevada  

SciTech Connect

A detailed, transient, three-dimensional, finite-difference groundwater flow model was created for the Mercury Valley Administrative Groundwater Basin (MVB). The MVB is a distinct groundwater basin as defined by the State of Nevada and is located partially within the boundary of the Nevada Test Site. This basin is being studied as a potential location for new industrial facilities and therefore would be subject to Nevada water-use limitations. The MVB model was used to estimate the volume of water that could be withdrawn from Mercury Valley without inducing laterally or vertically extensive water-table effects. In each model simulation, water-table drawdown was limited to a maximum of 0.5 m at the boundary of the basin and held within the screened interval of the well. Water withdrawal from Nevada groundwater basins is also limited to the State-defined perennial yield for that area. The perennial yield for the MVB is 27,036 m{sup 3}/day. The one existing water-supply well in Mercury Valley is capable of sustaining significantly higher withdrawal rates than it currently produces. Simulations showed this single well could produce 50 percent of the basin?s perennial yield with limited water-table drawdown. Pumping from six hypothetical water-supply wells was also simulated. Each hypothetical well was placed in an area of high hydraulic conductivity and far from the basin's boundaries. Each of these wells was capable of producing at least 50 percent of the basin's perennial yield. One of the hypothetical wells could simulate 100 percent of the perennial yield while staying within drawdown limitations. Multi-well simulations where two or more water-supply wells were simultaneously pumping were also conducted. These simulations almost always resulted in very limited lateral and vertical drawdown and produced 100 percent of Mercury Valley's perennial yield. A water-budget analysis was also conducted for each of the various stress simulations. Each of the stress scenarios was compared to a baseline scenario where existing water-supply wells in the model domain were pumped at 2003-2004 average pumping rates. Water-budget analyses showed increased flow from the constant-head boundaries on the north, east, and west sides of the model. Flow to the southern, head-dependent boundary and to springs in the Ash Meadows area remained unchanged.

A.B. Gilliam; R.W.H. Carroll; G. Pohll; R.L. Hershey

2006-01-01T23:59:59.000Z

223

Phase I Flow and Transport Model Document for Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada National Security Site, Nye County, Nevada, Revision 1  

Science Conference Proceedings (OSTI)

The Underground Test Area (UGTA) Corrective Action Unit (CAU) 97, Yucca Flat/Climax Mine, in the northeast part of the Nevada National Security Site (NNSS) requires environmental corrective action activities to assess contamination resulting from underground nuclear testing. These activities are necessary to comply with the UGTA corrective action strategy (referred to as the UGTA strategy). The corrective action investigation phase of the UGTA strategy requires the development of groundwater flow and contaminant transport models whose purpose is to identify the lateral and vertical extent of contaminant migration over the next 1,000 years. In particular, the goal is to calculate the contaminant boundary, which is defined as a probabilistic model-forecast perimeter and a lower hydrostratigraphic unit (HSU) boundary that delineate the possible extent of radionuclide-contaminated groundwater from underground nuclear testing. Because of structural uncertainty in the contaminant boundary, a range of potential contaminant boundaries was forecast, resulting in an ensemble of contaminant boundaries. The contaminant boundary extent is determined by the volume of groundwater that has at least a 5 percent chance of exceeding the radiological standards of the Safe Drinking Water Act (SDWA) (CFR, 2012).

Andrews, Robert

2013-09-01T23:59:59.000Z

224

A GIS COST MODEL TO ASSESS THE AVAILABILITY OF FRESHWATER, SEAWATER, AND SALINE GROUNDWATER FOR ALGAL BIOFUEL PRODUCTION IN THE UNITED STATES  

SciTech Connect

A key advantage of using microalgae for biofuel production is the ability of some algal strains to thrive in waters unsuitable for conventional crop irrigation such as saline groundwater or seawater. Nonetheless, the availability of sustainable water supplies will provide significant challenges for scale-up and development of algal biofuels. We conduct a limited techno-economic assessment based on the availability of freshwater, saline groundwater, and seawater for use in open pond algae cultivation systems. We explore water issues through GIS-based models of algae biofuel production, freshwater supply, and cost models for supplying seawater and saline groundwater. We estimate that combined, within the coterminous US these resources can support production on the order of 9.46E+7 m3 yr-1 (25 billion gallons yr-1) of renewable biodiesel. Achievement of larger targets requires the utilization of less water efficient sites and relatively expensive saline waters. Geographically, water availability is most favorable for the coast of the Gulf of Mexico and Florida peninsula, where evaporation relative to precipitation is moderate and various saline waters are economically available. As a whole, barren and scrub lands of the southwestern US have limited freshwater supplies so accurate assessment of alternative waters is critical.

Venteris, Erik R.; Skaggs, Richard; Coleman, Andre M.; Wigmosta, Mark S.

2013-03-15T23:59:59.000Z

225

Interfacial Pressures and Shocks in a Multiphase Flow mix Model  

Science Conference Proceedings (OSTI)

Multiphase flow models have been proposed for use in situations which have combined Rayleigh-Taylor (RTI) and Richtmyer-Meshkov (RMI) instabilities [2, 3]. Such an approach works poorly for the case of a heavy to light shock incidence on a developed interface. I suggest that this difficulty can be overcome by adding an additional source to the turbulence kinetic energy equation. A variety of constraints on such a source are considered. In this context it is observed that a new constraint on closures arises. This occurs because of the discontinuity within the shock responsible for the RMI. The proposed model (Shock Scattering) is shown to give useful results.

Klem, D E

2004-10-01T23:59:59.000Z

226

Mathematical modeling of methane flow in coal beds  

Science Conference Proceedings (OSTI)

The paper offers to describe the free and occlude gas filtration and diffusion in a coal bed by a numerical model in the form of a system of heterogenous parabolic equations. The gas flow as a shock and depression wave has been considered, and the desorption isotherm conditions for these waves to arise in a coal bed are formulated. By analyzing experimental data on cavities generated by a sudden coal and gas outburst, the authors construct the numerical model describing gas and coal mix outflow in a mine.

Fedorov, A.V.; Fedorchenko, I.A. [Russian Academy of Sciences, Novosibirsk (Russian Federation)

2009-01-15T23:59:59.000Z

227

A Monte Carlo model for seeded atomic flows in the transition regime  

Science Conference Proceedings (OSTI)

A simple model for the numerical determination of separation effects in seeded atomic gas flows is presented. The model is based on the known possibility to provide a statistically convergent estimate of the exact solution for a linear transport equation ... Keywords: Compressible flows, Monte Carlo simulation, Multi-component flows, Numerical methods, Rarefied flows

S. Longo; P. Diomede

2009-06-01T23:59:59.000Z

228

Modelling the convective flow in solar thermal receivers K.C. Yeh; G. Hughes & K. Lovegrove  

E-Print Network (OSTI)

Modelling the convective flow in solar thermal receivers K.C. Yeh; G. Hughes & K. Lovegrove density differences produced using the varying salt concentrations in a water tank. The flow to visualise #12;Modelling the Convective Flow in Solar Thermal Receivers Yeh the flow outside the cavity mouth

229

Coupling Air Flow Models to Load/Energy Models and Implications for  

NLE Websites -- All DOE Office Websites (Extended Search)

Coupling Air Flow Models to Load/Energy Models and Implications for Coupling Air Flow Models to Load/Energy Models and Implications for Envelope Component Testing and Modeling Speaker(s): Brent Griffith Date: July 30, 2002 - 12:00pm Location: Bldg. 90 Seminar Host/Point of Contact: Dariush Arasteh Air models allow accounting for air temperature variations within a thermal zone or along the surface of an envelope component. A recently completed ASHRAE research project (RP-1222) produced a source code toolkit focused on coupling airflow models to load routines typical of whole building energy simulation. The two modeling domains are computed separately (and iteratively) with relevant temperature boundary conditions passed back and forth. One of the air models in the toolkit is a new contribution to crude/fast airflow modeling that is based on solving the Euler equation

230

Discrete-element modeling of particulate aerosol flows  

Science Conference Proceedings (OSTI)

A multiple-time step computational approach is presented for efficient discrete-element modeling of aerosol flows containing adhesive solid particles. Adhesive aerosol particulates are found in numerous dust and smoke contamination problems, including smoke particle transport in the lungs, particle clogging of heat exchangers in construction vehicles, industrial nanoparticle transport and filtration systems, and dust fouling of electronic systems and MEMS components. Dust fouling of equipment is of particular concern for potential human occupation on dusty planets, such as Mars. The discrete-element method presented in this paper can be used for prediction of aggregate structure and breakup, for prediction of the effect of aggregate formation on the bulk fluid flow, and for prediction of the effects of small-scale flow features (e.g., due to surface roughness or MEMS patterning) on the aggregate formation. After presentation of the overall computational structure, the forces and torques acting on the particles resulting from fluid motion, particle-particle collision, and adhesion under van der Waals forces are reviewed. The effect of various parameters of normal collision and adhesion of two particles are examined in detail. The method is then used to examine aggregate formation and particle clogging in pipe and channel flow.

Marshall, J.S. [School of Engineering, University of Vermont, 33 Colchecter Avenue, Burlington, Vermont 05405 (United States)], E-mail: jeffm@cems.uvm.edu

2009-03-20T23:59:59.000Z

231

Chemistry Resolved Kinetic Flow Modeling of TATB Based Explosives  

SciTech Connect

Detonation waves in insensitive, TATB based explosives are believed to have multi-time scale regimes. The initial burn rate of such explosives has a sub-microsecond time scale. However, significant late-time slow release in energy is believed to occur due to diffusion limited growth of carbon. In the intermediate time scale concentrations of product species likely change from being in equilibrium to being kinetic rate controlled. They use the thermo-chemical code CHEETAH linked to an ALE hydrodynamics code to model detonations. They term their model chemistry resolved kinetic flow as CHEETAH tracks the time dependent concentrations of individual species in the detonation wave and calculates EOS values based on the concentrations. A HE-validation suite of model simulations compared to experiments at ambient, hot, and cold temperatures has been developed. They present here a new rate model and comparison with experimental data.

Vitello, P A; Fried, L E; Howard, W M; Levesque, G; Souers, P C

2011-07-21T23:59:59.000Z

232

Characterizing two-phase flow relative permeabilities in chemical flooding using a pore-scale network model  

E-Print Network (OSTI)

simultaneous flow of multiphase fluids in a porous medium byin porous media-pore network models and multiphase flow,simulating multiphase flow and transport processes in porous

Liu, Qingjie; Shen, Pingping; Wu, Yu-Shu

2008-01-01T23:59:59.000Z

233

A Comparison of the AC and DC Power Flow Models for LMP Calculations  

E-Print Network (OSTI)

shifting transformers is often dependent upon the transformer's tap value. Last, the power flow modelsA Comparison of the AC and DC Power Flow Models for LMP Calculations Thomas J. Overbye, Xu Cheng power flow model for LMP-based market calculations. The paper first provides a general discussion

234

Designing intelligent disaster prediction models and systems for debris-flow disasters in Taiwan  

Science Conference Proceedings (OSTI)

Effective disaster prediction relies on using correct disaster decision model to predict the disaster occurrence accurately. This study proposes three effective debris-flow prediction models and an inference engine to predict and decide the debris-flow ... Keywords: Back-propagation network, Debris-flow prediction models, Decision support system, Disaster prevention, Mobile multimedia communications

Hsu-Yang Kung; Chi-Hua Chen; Hao-Hsiang Ku

2012-04-01T23:59:59.000Z

235

Model Free Closed-Loop Flow Control ERCAN ATAM, LIONEL MATHELIN, LAURENT CORDIER  

E-Print Network (OSTI)

Model Free Closed-Loop Flow Control ERCAN ATAM, LIONEL MATHELIN, LAURENT CORDIER *CNRS- Mathelin-Cordier (LIMSI-CNRS,IP') Model Free Closed-Loop Flow Control ECCOMAS'12 1 / 21 #12;Outline 1 and some future work Atam- Mathelin-Cordier (LIMSI-CNRS,IP') Model Free Closed-Loop Flow Control ECCOMAS'12

Mathelin, Lionel

236

Hanford Site Groundwater Monitoring for Fiscal Year 2003  

SciTech Connect

This report presents the results of groundwater and vadose zone monitoring and remediation for fiscal year 2003 (October 2002 through September 2003) on the U.S. Department of Energy's Hanford Site, Washington. The most extensive contaminant plumes in groundwater are tritium, iodine-129, and nitrate, which all had multiple sources and are very mobile in groundwater. The largest portions of these plumes are migrating from the central Hanford Site to the southeast, toward the Columbia River. Concentrations of tritium, nitrate, and some other contaminants continued to exceed drinking water standards in groundwater discharging to the river in some locations. However, contaminant concentrations in river water remained low and were far below standards. Carbon tetrachloride and associated organic constituents form a relatively large plume beneath the central part of the Hanford Site. Hexavalent chromium is present in smaller plumes beneath the reactor areas along the river and beneath the central part of the site. Strontium-90 exceeds standards beneath all but one of the reactor areas, and technetium-99 and uranium are present in the 200 Areas. Uranium exceeds standards in the 300 Area in the south part of the Hanford Site. Minor contaminant plumes with concentrations greater than standards include carbon-14, cesium-137, cis-1,2-dichloroethene, cyanide, fluoride, plutonium, and trichloroethene. Monitoring for the ''Comprehensive Environmental Response, Compensation, and Liability Act'' is conducted in 11 groundwater operable units. The purpose of this monitoring is to define and track plumes and to monitor the effectiveness of interim remedial actions. Interim groundwater remediation in the 100 Areas continued with the goal of reducing the amount of chromium (100-K, 100-D, and 100-H) and strontium-90 (100-N) reaching the Columbia River. The objective of two interim remediation systems in the 200 West Area is to prevent the spread of carbon tetrachloride and technetium-99/uranium plumes. ''Resource Conservation and Recovery Act'' groundwater monitoring continued at 24 waste management areas during fiscal year 2003: 15 under interim or final status detection programs and data indicate that they are not adversely affecting groundwater; 7 under interim status groundwater quality assessment programs to assess contamination; and 2 under final status corrective-action programs. During calendar year 2003, drillers completed seven new RCRA monitoring wells, nine wells for CERCLA, and two wells for research on chromate bioremediation. Vadose zone monitoring, characterization, and remediation continued in fiscal year 2003. Remediation and associated monitoring continued at a soil-vapor extraction system in the 200 West Area, which removes gaseous carbon tetrachloride from the vadose zone. Soil vapor also was sampled to locate carbon tetrachloride sites with the potential to impact groundwater in the future. DOE uses geophysical methods to monitor potential movement of contamination beneath single-shell tank farms. During fiscal year 2003, DOE monitored selected boreholes within each of the 12 single-shell tank farms. In general, the contaminated areas appeared to be stable over time. DOE drilled new boreholes at the T Tank Farm to characterize subsurface contamination near former leak sites. The System Assessment Capability is a set of computer modules simulating movement of contaminants from waste sites through the vadose zone and groundwater. In fiscal year 2003, it was updated with the addition of an atmospheric transport module and with newer versions of models including an updated groundwater flow and transport model.

Hartman, Mary J.; Morasch, Launa F.; Webber, William D.

2004-04-12T23:59:59.000Z

237

Computational Fluid Dynamics Modeling of Atmospheric Flow Applied to Wind Energy Research.  

E-Print Network (OSTI)

??High resolution atmospheric flow modeling using computational fluid dynamics (CFD) has many applications in the wind energy industry. A well designed model can accurately calculate… (more)

Russell, Alan

2009-01-01T23:59:59.000Z

238

CFD modeling of entrained-flow coal gasifiers with improved physical and chemical sub-models  

Science Conference Proceedings (OSTI)

Optimization of an advanced coal-fired integrated gasification combined cycle system requires an accurate numerical prediction of gasifier performance. While the turbulent multiphase reacting flow inside entrained-flow gasifiers has been modeled through computational fluid dynamic (CFD), the accuracy of sub-models requires further improvement. Built upon a previously developed CFD model for entrained-flow gasification, the advanced physical and chemical sub-models presented here include a moisture vaporization model with consideration of high mass transfer rate, a coal devolatilization model with more species to represent coal volatiles and heating rate effect on volatile yield, and careful selection of global gas phase reaction kinetics. The enhanced CFD model is applied to simulate two typical oxygen-blown entrained-flow configurations including a single-stage down-fired gasifier and a two-stage up-fired gasifier. The CFD results are reasonable in terms of predicted carbon conversion, syngas exit temperature, and syngas exit composition. The predicted profiles of velocity, temperature, and species mole fractions inside the entrained-flow gasifier models show trends similar to those observed in a diffusion-type flame. The predicted distributions of mole fractions of major species inside both gasifiers can be explained by the heterogeneous combustion and gasification reactions and the homogeneous gas phase reactions. It was also found that the syngas compositions at the CFD model exits are not in chemical equilibrium, indicating the kinetics for both heterogeneous and gas phase homogeneous reactions are important. Overall, the results achieved here indicate that the gasifier models reported in this paper are reliable and accurate enough to be incorporated into process/CFD co-simulations of IGCC power plants for systemwide design and optimization.

Ma, J.; Zitney, S.

2012-01-01T23:59:59.000Z

239

Groundwater monitoring in china  

Science Conference Proceedings (OSTI)

Groundwater accounts for 1/3 of the water resources in China and is indispensable for water supply and ecological support in many areas, especially in North China. But unreasonable groundwater development has caused some serious geo-environment problems ...

Qingcheng He; Cai Li

2006-01-01T23:59:59.000Z

240

A Conceptual model of coupled biogeochemical and hydrogeological processes affected by in situ Cr(VI) bioreduction in groundwater at Hanford 100H Site  

E-Print Network (OSTI)

in Groundwater at Hanford 100H Site B.Faybishenko, P.E.Long,Cr(VI) contaminated groundwater at Hanford 100H site. A slowHRC TM ), was injected in Hanford sediments to stimulate

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

A Darcy law for the drift velocity in a two-phase flow model  

Science Conference Proceedings (OSTI)

This work deals with the design and numerical approximation of an Eulerian mixture model for the simulation of two-phase dispersed flows. In contrast to the more classical two-fluid or Drift-flux models, the influence of the velocity disequilibrium is ... Keywords: Bubbly flows, Chapman-Enskog expansion, Darcy law, Drift-flux, Riemann solver, Two-phase flows

H. Guillard; F. Duval

2007-05-01T23:59:59.000Z

242

FITOVERT: A dynamic numerical model of subsurface vertical flow constructed wetlands  

Science Conference Proceedings (OSTI)

This paper introduces a mathematical model (FITOVERT) specifically developed to simulate the behaviour of vertical subsurface flow constructed wetlands (VSSF-CWs). One of the main goals of the development of FITOVERT was to keep the complexity of the ... Keywords: Constructed wetlands, Hydrodynamics, Modelling, Reactive transport, Unsaturated flow, Vertical subsurface flow

D. Giraldi; M. de Michieli Vitturi; R. Iannelli

2010-05-01T23:59:59.000Z

243

A reaction-based paradigm to model reactive chemical transport in groundwater with general kinetic and equilibrium reactions  

Science Conference Proceedings (OSTI)

This paper presents a reaction-based water quality transport model in subsurface flow systems. Transport of chemical species with a variety of chemical and physical processes is mathematically described by M partial differential equations (PDEs). Decomposition via Gauss-Jordan column reduction of the reaction network transforms M species reactive transport equations into two sets of equations: a set of thermodynamic equilibrium equations representing NE equilibrium reactions and a set of reactive transport equations of M-NE kinetic-variables involving no equilibrium reactions (a kinetic-variable is a linear combination of species). The elimination of equilibrium reactions from reactive transport equations allows robust and efficient numerical integration. The model solves the PDEs of kinetic-variables rather than individual chemical species, which reduces the number of reactive transport equations and simplifies the reaction terms in the equations. A variety of numerical methods are investigated for solving the coupled transport and reaction equations. Simulation comparisons with exact solutions were performed to verify numerical accuracy and assess the effectiveness of various numerical strategies to deal with different application circumstances. Two validation examples involving simulations of uranium transport in soil columns are presented to evaluate the ability of the model to simulate reactive transport with complex reaction networks involving both kinetic and equilibrium reactions.

Zhang, Fan [ORNL; Yeh, Gour-Tsyh [University of Central Florida, Orlando; Parker, Jack C [ORNL; Brooks, Scott C [ORNL; Pace, Molly [ORNL; Kim, Young Jin [ORNL; Jardine, Philip M [ORNL; Watson, David B [ORNL

2007-01-01T23:59:59.000Z

244

Fladmark. Parallel simulation of multiphase/multicomponent flow models  

E-Print Network (OSTI)

Summary. The simulation of flow in porous media is a computationally demanding task. Thermodynamical equilibrium calculations and complex, heterogeneous geological structures normally gives a multiphysics/multidomain problem to solve. Thus, efficient solution methods are needed. The research simulator Athena is a 3D, multiphase, multicomponent, porous media flow simulator. A parallel version of the simulator was developed based on a non-overlapping domain decomposition strategy, where the domains are defined a-priori from e.g. geological data. Selected domains are refined with locally matching grids, giving a globally non-matching, unstructured grid. In addition to the space domain, novel algorithms for parallel processing in time based on a predictor-corrector strategy has been successfully implemented. We discuss how the domain decomposition framework can be used to include different physical and numerical models in selected sub-domains. Also we comment on how the two-level solver relates to multiphase upscaling techniques. Adding communication functionality enables the original serial version to run on each sub-domain in parallel. Motivated by the need for larger time steps, an implicit formulation of the mass transport equations has been formulated and implemented in the existing parallel framework. Further, as the Message Passing Interface (MPI) is used for communication, the simulator is highly portable. Through benchmark experiments, we test the new formulation on platforms ranging from commercial super-computers to heterogeneous networks of workstations. 1

Erlend Øian; Magne S. Espedal; I. Garrido; G. E. Fladmark

2004-01-01T23:59:59.000Z

245

Coupled rock motion and gas flow modeling in blasting  

SciTech Connect

The spherical element computer code DMC (Distinct Motion Code) used to model rock motion resulting from blasting has been enhanced to allow routine computer simulations of bench blasting. The enhancements required for bench blast simulation include: (1) modifying the gas flow portion of DMC, (2) adding a new explosive gas equation of state capability, (3) modifying the porosity calculation, and (4) accounting for blastwell spacing parallel to the face. A parametric study performed with DMC shows logical variation of the face velocity as burden, spacing, blastwell diameter and explosive type are varied. These additions represent a significant advance in the capability of DMC which will not only aid in understanding the physics involved in blasting but will also become a blast design tool. 8 refs., 7 figs., 1 tab.

Preece, D.S. (Sandia National Labs., Albuquerque, NM (United States)); Knudsen, S.D. (RE/SPEC, Inc., Albuquerque, NM (United States))

1991-01-01T23:59:59.000Z

246

Assessment of groundwater management at Hanford  

SciTech Connect

A comprehensive review of the groundwater management and environmental monitoring programs at the Hanford reservation was initiated in 1973. A large number of recommendations made as a result of this review are summarized. The purpose of the Hanford Hydrology Program is to maintain a groundwater surveillance network to assess contamination of the natural water system. Potential groundwater contamination is primarily a function of waste management decisions. The review revealed that although the hydrology program would greatly benefit from additional improvements, it is adequate to predict levels of contaminants present in the groundwater system. Studies are presently underway to refine advanced mathematical models to use results of the hydrologic investigation in forecasting the response of the system to different long-term management decisions. No information was found which indicates that a hazard through the groundwater pathway presently exists as a result of waste operations at Hanford. (CH)

Deju, R.A.

1975-02-11T23:59:59.000Z

247

FACT (Version 2.0) - Subsurface Flow and Contaminant Transport Documentation and User's Guide  

Science Conference Proceedings (OSTI)

This report documents a finite element code designed to model subsurface flow and contaminant transport, named FACT. FACT is a transient three-dimensional, finite element code designed to simulate isothermal groundwater flow, moisture movement, and solute transport in variably saturated and fully saturated subsurface porous media.

Aleman, S.E.

2000-05-05T23:59:59.000Z

248

An Expert Elicitation Process in Support of Groundwater Model Evaluation for Frenchman Flat, Nevada National Security Site  

SciTech Connect

The U.S. Department of Energy is implementing corrective actions at facilities where nuclear-related operations were conducted in Nevada. Among the most significant sites being addressed are the locations of underground nuclear tests on the Nevada National Security Site (NNSS). The process for implementing corrective actions for the Underground Test Area (UGTA) locations is defined in Appendix VI of a Federal Facility Agreement and Consent Order (1996, as amended). In broad terms, Appendix VI describes a Corrective Action Investigation followed by a Corrective Action Decision, and implementation of a Corrective Action Plan prior to closure. The Frenchman Flat Corrective Action Unit (CAU) is farthest along in the UGTA corrective action process. It includes ten underground tests within the Frenchman Flat topographic basin, in the southeastern portion of the NNSS. Data have been collected from drilling exploration, hydrologic testing, and field and laboratory studies. Modeling has been completed at a variety of scales and focusing on a variety of flow and transport aspects ranging from regional boundary conditions to process dynamics within a single nuclear cavity. The culmination of the investigations is a transport model for the Frenchman Flat CAU (Stoller Navarro Joint Venture, 2009) that has undergone rigorous peer review and been accepted by the State of Nevada, setting the stage for the Corrective Action Decision and progression from the investigation phase to the corrective action phase of the project.

Chapman Jenny,Pohlmann Karl

2011-02-01T23:59:59.000Z

249

Physical Modeling of Flow Field inside Urban Street Canyons  

Science Conference Proceedings (OSTI)

The flow characteristics inside urban street canyons were studied in a laboratory water channel. The approaching flow direction was horizontal and perpendicular to the street axis. The street width was adjusted to form street canyons of aspect ...

Xian-Xiang Li; Dennis Y. C. Leung; Chun-Ho Liu; K. M. Lam

2008-07-01T23:59:59.000Z

250

A Hidden Markov Model Perspective on Regimes and Metastability in Atmospheric Flows  

Science Conference Proceedings (OSTI)

In this study, data from three atmospheric models are analyzed to investigate the existence of atmospheric flow regimes despite nearly Gaussian statistics of the planetary waves in these models. A hierarchy of models is used, which describes the ...

Christian Franzke; Daan Crommelin; Alexander Fischer; Andrew J. Majda

2008-04-01T23:59:59.000Z

251

Unsaturated flow modeling of a retorted oil shale pile.  

SciTech Connect

The objective of this study was to demonstrate the capabilities of the UNSAT1D model for assessing this potential threat to the environment by understanding water movement through spent shale piles. Infiltration, redistribution, and drainage of water in a spent shale pile were simulated with the UNSAT1D model for two test cases: (1) an existing 35 m pile; and (2) a transient pile growing at a rate of 10 m/year for 5 years. The first test case simulated three different layering scenarios with each one being run for 1 year. The second test case simulated two different initial moisture contents in the pile with each simulation being run for 30 years. Grand Junction and Rifle, Colorado climatological data were used to provide precipitation and potential evapotranspiration for a wet (1979) and dry (1976) year, respectively. Hydraulic properties obtained from the literature on Paraho process spent shale soil, and clay were used as model input parameters to describe water retention and hydraulic conductivity characteristics. Plant water uptake was not simulated in either test case. The two test cases only consider the evaporation component of evapotranspiration, thereby maximizing the amount of water infiltrating into the pile. The results of the two test cases demonstrated that the UNSAT1D model can adequately simulate flow in a spent shale pile for a variety of initial and boundary conditions, hydraulic properties, and pile configurations. The test cases provided a preliminary sensitivity analysis in which it was shown that the material hydraulic properties, material layering, and initial moisture content are the principal parameters influencing drainage from the base of a pile. 34 figures, 4 tables.

Bond, F.W.; Freshley, M.D.; Gee, G.W.

1982-10-01T23:59:59.000Z

252

Pore-scale modeling of the impact of surrounding flow behavior on multiphase flow properties.  

E-Print Network (OSTI)

??Accurate predictions of macroscopic multiphase flow properties, such as relative permeability and capillary pressure, are necessary for making key decisions in reservoir engineering. These properties… (more)

Petersen, Robert Thomas

2010-01-01T23:59:59.000Z

253

Dual Permeability Modeling of Flow in a Fractured Geothermal Reservoir  

DOE Green Energy (OSTI)

A three dimensional fracture system synthesis and flow simulation has been developed to correlate drawdown characteristics measured in a geothermal well and to provide the basis for an analysis of tracer tests. A new dual permeability approach was developed which incorporates simulations at two levels to better represent a discrete fracture system within computer limitations. The first incorporates a discrete simulation of the largest fractures in the system plus distributed or representative element simulation of the smaller fractures. the second determines the representative element properties by discrete simulation of the smaller fractures. The fracture system was synthesized from acoustic televiewer data on the orientation and separation of three distinct fracture sets, together with additional data from the literature. Lognormal and exponential distributions of fracture spacing and radius were studied with the exponential distribution providing more reasonable results. Hydraulic apertures were estimated as a function of distance from the model boundary to a constant head boundary. Mean values of 6.7, 101 and 46 {micro}m were chosen as the most representative values for the three fracture sets. Recommendations are given for the additional fracture characterization needed to reduce the uncertainties in the model.

Miller, John D.; Allman, David W.

1986-01-21T23:59:59.000Z

254

Dual permeability modeling of flow in a fractured geothermal reservoir  

DOE Green Energy (OSTI)

A three dimensional fracture system synthesis and flow simulation has been developed to correlate drawdown characteristics measured in a geothermal well and to provide the basis for an analysis of tracer tests. A new dual permeability approach was developed which incorporates simulations at two levels to better represent a discrete fracture system within computer limitations. The first incorporates a discrete simulation of the largest fractures in the system plus distributed or representative element stimulation of the smaller fractures. The second determines the representative element properties by discrete simulation of the smaller fractures. The fracture system was synthesized from acoustic televiewer data on the orientation and separation of three distinct fracture sets, together with additional data from the literature. Lognormal and exponential distributions of fracture spacing and radius were studied with the exponential distribution providing more reasonable results. Hydraulic apertures were estimated as a function of distance from the model boundary to a constant head boundary. Mean values of 6.7, 101 and 46 ..mu..m were chosen as the most representative values for the three fracture sets. Recommendations are given for the additional fracture characterization needed to reduce the uncertainties in the model. 20 refs., 6 figs.

Miller, J.D.; Allman, D.W.

1986-01-01T23:59:59.000Z

255

A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus  

SciTech Connect

This paper provides an overview of the variable refrigerant flow heat pump computer model included with the Department of Energy's EnergyPlusTM whole-building energy simulation software. The mathematical model for a variable refrigerant flow heat pump operating in cooling or heating mode, and a detailed model for the variable refrigerant flow direct-expansion (DX) cooling coil are described in detail.

Raustad, Richard A. [Florida Solar Energy Center

2013-01-01T23:59:59.000Z

256

Direct pore-level modeling of incompressible fluid flow in porous media  

Science Conference Proceedings (OSTI)

We present a dynamic particle-based model for direct pore-level modeling of incompressible viscous fluid flow in disordered porous media. The model is capable of simulating flow directly in three-dimensional high-resolution micro-CT images of rock samples. ... Keywords: Incompressible fluid flow, Micro-CT X-ray imaging, Moving particle semi-implicit, Particle-based methods, Porous media

Saeed Ovaysi; Mohammad Piri

2010-09-01T23:59:59.000Z

257

Development of kinetic model reduction framework and its application in realistic flow simulation.  

E-Print Network (OSTI)

??The main objective of this research is to develop a kinetic model reduction framework that enables incorporation of detailed chemistry with realistic flow simulation. Comprehensive… (more)

He, Kaiyuan, 1986-

2010-01-01T23:59:59.000Z

258

E13: An Experimentally-based Flow Stress Model for Cortical Bone  

Science Conference Proceedings (OSTI)

Developed here is a micro-scale-based flow stress model of cortical bone. In order to ... Catalysts by Using the Metal Ion-reducing Bacterium Shewanella Algae.

259

A Site-Scale Model For Fluid And Heat Flow In The Unsaturated...  

Open Energy Info (EERE)

repository. The modeling approach is based on a mathematical formulation of coupled multiphase, multicomponent fluid and heat flow through porous and fractured rock. Fracture...

260

Conjunctive management of groundwater and surface water resources in the Upper Ovens River Valley.  

E-Print Network (OSTI)

??Regression analysis produced equations for relating Ovens River levels to groundwater levels with a high correlation. These equations can relate stream flow objectives to corresponding… (more)

Lovell, Daniel Martin

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

On enhanced non-linear free surface flow simulations with a hybrid LBM-VOF model  

Science Conference Proceedings (OSTI)

In this paper, we present extensions, extensive validations and applications of our previously published hybrid volume-of-fluid-based (VOF) model for the simulation of free-surface flow problems. For the solution of the flow field, the lattice Boltzmann ... Keywords: Free surface, Lattice Boltzmann method, PLIC, Plunging breaker, Potential flow, Volume of fluid

Christian F. JaníEn; Stephan T. Grilli; Manfred Krafczyk

2013-01-01T23:59:59.000Z

262

Groundwater Age-Dating for Water Resource Characterization  

The LLNL Groundwater Noble Gas Mass Spectrometry Facility and Capability offers: Less model-dependent than tritium age dating: Traditional tritium age ...

263

Geochemical and Isotopic Evaluation of Groundwater Movement in Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nevada, Rev. No.: 0  

SciTech Connect

This report describes the results of a comprehensive geochemical evaluation of the groundwater flow system in the Yucca Flat/Climax Mine Corrective Action Unit (CAU). The main objectives of this study are to identify probable pathways for groundwater flow within the study area and to develop constraints on groundwater transit times between selected data collection sites. This work provides an independent means of testing and verifying predictive flow models being developed for this CAU using finite element methods. The Yucca Flat/Climax Mine CAU constitutes the largest of six underground test areas on the Nevada Test Site (NTS) specified for remedial action in the ''Federal Facility Agreement and Consent Order''. A total of 747 underground nuclear detonations were conducted in this CAU. Approximately 23 percent of these detonations were conducted below or near the water table, resulting in groundwater contamination in the vicinity and possibly downgradient of these underground test locations. Therefore, a rigorous evaluation of the groundwater flow system in this CAU is necessary to assess potential long-term risks to the public water supply at downgradient locations.

Farnham, Irene

2006-02-01T23:59:59.000Z

264

Use of vertical slip flow and flooding models in LOCA analysis  

SciTech Connect

Vertical slip flow and flooding models, which have been incorporated in a version of the RELAP4 computer code by Aerojet Nuclear Company have led to significant improvements in modeling nuclear reactor coolant system phenomena during postulated large and small break loss-of-coolant accidents. The vertical slip flow model computes the separated fluid component velocities and directions at vertical flow junctions. Use of the slip model allows the energy transfer between volumes to be based on individual liquid and vapor component flows rather than on the net junction flow. Continuity and momentum equations are unaffected by the addition of slip. The vertical flow slip model logic is based on the assumption that gravity forces dominate causing slip between phases. 7 references (auth)

Fischer, S.R.

1975-01-01T23:59:59.000Z

265

A Multi-scale Agent-Based Distributed Simulation Framework for Groundwater Pollution Management  

Science Conference Proceedings (OSTI)

Groundwater is like dark matter--we know very little apart from the fact that it is hugely important. Given the scarcity of data, mathematical modelling can come to the rescue but existing groundwater models are mainly restricted to simulate the transport ... Keywords: groundwater, bioremediation, distributed simulation, multi-scale modelling, agent-based systems, individual-based models

Susanne I. Schmidt; Cristian Picioreanu; Bart Craenen; Rae Mackay; Jan-Ulrich Kreft; Georgios Theodoropoulos

2011-09-01T23:59:59.000Z

266

Modeling, Analysis and Simulation of Multiscale Preferential Flow - 8/05-8/10 - Final Report  

SciTech Connect

The research agenda of this project are: (1) Modeling of preferential transport from mesoscale to macroscale; (2) Modeling of fast flow in narrow fractures in porous media; (3) Pseudo-parabolic Models of Dynamic Capillary Pressure; (4) Adaptive computational upscaling of flow with inertia from porescale to mesoscale; (5) Adaptive modeling of nonlinear coupled systems; and (6) Adaptive modeling and a-posteriori estimators for coupled systems with heterogeneous data.

Ralph Showalter; Malgorzata Peszynska

2012-07-03T23:59:59.000Z

267

Revised Benchmark Problem for modeling of metal flow and metal ...  

Science Conference Proceedings (OSTI)

The literature is scarce when it comes to benchmark problems for MHD flow in a cell and those cases which are available often suffer from insufficient level of ...

268

Simplified Wind Flow Model for the Estimation of Aerodynamic ...  

Science Conference Proceedings (OSTI)

... and the low-frequency fluctuations present in the ABL flow are suppressed; that is, the peak energy of the ... For personal use only; all rights reserved. ...

2013-08-19T23:59:59.000Z

269

TRACER: an EXCEL workbook to calculate mean residence time in groundwater by use of tracers CFC-11, CFC-12 and tritium  

Science Conference Proceedings (OSTI)

An EXCEL workbook is presented for calculating the mean residence time of groundwater based on the environmental tracers, tritium, CFC-11 and CFC-12. The program TRACER is written in Visual Basic for Application language and uses piston, exponential, ... Keywords: environmental tracer, exit-age distribution, exponential model, piston flow, turnover time

Serdar Bayari

2002-06-01T23:59:59.000Z

270

Application of Artificial Neural Networks to Complex Groundwater Management Problems  

SciTech Connect

As water quantity and quality problems become increasingly severe, accurate prediction and effective management of scarcer water resources will become critical. In this paper, the successful application of artificial neural network (ANN) technology is described for three types of groundwater prediction and management problems. In the first example, an ANN was trained with simulation data from a physically based numerical model to predict head (groundwater elevation) at locations of interest under variable pumping and climate conditions. The ANN achieved a high degree of predictive accuracy, and its derived state-transition equations were embedded into a multiobjective optimization formulation and solved to generate a trade-off curve depicting water supply in relation to contamination risk. In the second and third examples, ANNs were developed with real-world hydrologic and climate data for different hydrogeologic environments. For the second problem, an ANN was developed using data collected for a 5-year, 8-month period to predict heads in a multilayered surficial and limestone aquifer system under variable pumping, state, and climate conditions. Using weekly stress periods, the ANN substantially outperformed a well-calibrated numerical flow model for the 71-day validation period, and provided insights into the effects of climate and pumping on water levels. For the third problem, an ANN was developed with data collected automatically over a 6-week period to predict hourly heads in 11 high-capacity public supply wells tapping a semiconfined bedrock aquifer and subject to large well-interference effects. Using hourly stress periods, the ANN accurately predicted heads for 24-hour periods in all public supply wells. These test cases demonstrate that the ANN technology can solve a variety of complex groundwater management problems and overcome many of the problems and limitations associated with traditional physically based flow models.

Coppola, Emery [NOAH LLC. (United States)], E-mail: noah.llc@mail.com; Poulton, Mary [University of Arizona, Department of Mining and Geological Engineering (United States); Charles, Emmanuel [U.S. Geological Survey (United States); Dustman, John [Summit EnviroSolutions (United States); Szidarovszky, Ferenc [University of Arizona, Department of Systems and Industrial Engineering (United States)

2003-12-15T23:59:59.000Z

271

Portsmouth Site Feeds Bacteria to Render Hazardous Groundwater Waste  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Portsmouth Site Feeds Bacteria to Render Hazardous Groundwater Portsmouth Site Feeds Bacteria to Render Hazardous Groundwater Waste Harmless Portsmouth Site Feeds Bacteria to Render Hazardous Groundwater Waste Harmless April 2, 2012 - 12:00pm Addthis Neil Smith puts a trained eye on the pressure and flow of a food-grade com¬pound being injected into an under¬ground plume of hazardous waste near the X-720 Maintenance Facility at the DOE Piketon Site. The sodium lactate compound promotes bacterial growth in the groundwater that turns hazardous waste into harmless end-products. Neil Smith puts a trained eye on the pressure and flow of a food-grade com¬pound being injected into an under¬ground plume of hazardous waste near the X-720 Maintenance Facility at the DOE Piketon Site. The sodium lactate compound promotes bacterial growth in the groundwater that turns

272

Hanford Site Groundwater Monitoring for Fiscal Year 1998  

Science Conference Proceedings (OSTI)

This report presents the results of groundwater and vadose-zone monitoring and remediation for fiscal year (FY) 1998 on the Word Site, Washington. Soil-vapor extraction in the 200-West Area removed 777 kg of carbon tetrachloride in FY 1998, for a total of 75,490 kg removed since remediation began in 1992. Spectral gamma logging and evaluation of historical gross gamma logs near tank farms and liquid-disposal sites in the 200 Areas provided information on movement of contaminants in the vadose zone. Water-level monitoring was performed to evaluate groundwater-flow directions, to track changes in water levels, and to relate such changes to evolving disposal practices. Water levels over most of the Hanford Site continued to decline between June 1997 and June 1998. The most widespread radiological contaminant plumes in groundwater were tritium and iodine-129. Concentrations of technetium-99, uranium, strontium-90, and carbon-14 also exceeded drinking water standards in smaller plumes. Plutonium and cesium-137 exceeded standards only near the 216-B-5 injection well. Derived concentration guide levels specified in U.S. Department of Energy Order 5400.5 were exceeded for tritium, uranium, strontium-90, and plutonium in small plumes or single wells. One well completed in the basalt-confined aquifer beneath the 200-East Area exceeded the drinking water standard for technetium-99. Nitrate is the most extensive chemical contaminant. Carbon tetrachloride, chloroform, chromium, cis-l, Z-dichloroethylene, fluoride, and trichloroethylene also were present in smaller areas at levels above their maximum contaminant levels. Cyanide concentrations were elevated in one area but were below the maximum contaminant level. Tetrachloroethylene exceeded its maximum contaminant level in several wells in the 300 Area for the first time since the 1980s. Metals such as aluminum, cadmium, iron, manganese, and nickel exceeded their maximum contaminant levels in filtered samples from numerous wells; they are believed to represent natural components of groundwater. Resource Conservation and Recovery Act of 1976 groundwater monitoring continued at 25 waste management areas during FY 1998: 17 under detection programs and data indicate that they are not adversely affecting groundwater, 6 under interim-status groundwater-quality-assessment programs to assess possible contamination, and 2 under final-status corrective-action programs. Groundwater remediation in the 100 Areas continued to reduce the amount of strontium-90 (100-N) and chromium (100-K, D, and H) reaching the Columbia River. Two systems in the 200-West Area operated to prevent the spread of carbon tetrachloride and technetide uranium plumes. Groundwater monitoring continued at these sites and at other sites where there is no active remediation. A three-dimensional, numerical groundwater model was applied to simulate radionuclide movement from sources in the 200 Areas following site closure in 2050. Contaminants will continue to move toward the southeast and north (through Gable Gap), but the areas with levels exceeding drinking water standards will diminish.

Hartman, M.J. [and others

1999-03-24T23:59:59.000Z

273

Development of a model to predict flow oscillations in low-flow sodium boiling  

E-Print Network (OSTI)

An experimental and analytical program has been carried out in order to better understand the cause and effect of flow oscillations in boiling sodium systems. These oscillations have been noted in previous experiments with ...

Levin, Alan Edward

1980-01-01T23:59:59.000Z

274

A Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca  

Open Energy Info (EERE)

Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca Mountain, Nevada Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca Mountain, Nevada Details Activities (0) Areas (0) Regions (0) Abstract: A three-dimensional unsaturated-zone numerical model has been developed to simulate flow and distribution of moisture, gas and heat at Yucca Mountain, Nevada, a potential repository site for high-level radioactive waste. The model takes into account the simultaneous flow dynamics of liquid water, vapor, air and heat in the highly heterogeneous, fractured porous rock in the unsaturated zone (UZ). This model is intended for use in the prediction of the current and future conditions in the UZ so

275

Groundwater and Wells (Nebraska)  

Energy.gov (U.S. Department of Energy (DOE))

This section describes regulations relating to groundwater protection, water wells, and water withdrawals, and requires the registration of all water wells in the state.

276

Modelling two-phase flow in porous media at the pore scale using the volume-of-fluid method  

Science Conference Proceedings (OSTI)

We present a stable numerical scheme for modelling multiphase flow in porous media, where the characteristic size of the flow domain is of the order of microns to millimetres. The numerical method is developed for efficient modelling of multiphase flow ... Keywords: Pore-scale modelling, Porous media, Two-phase flow, Volume of fluid

Ali Q. Raeini; Martin J. Blunt; Branko Bijeljic

2012-07-01T23:59:59.000Z

277

Estimation of Groundwater Recharge at Pahute Mesa using the Chloride Mass-Balance Method  

SciTech Connect

Groundwater recharge on Pahute Mesa was estimated using the chloride mass-balance (CMB) method. This method relies on the conservative properties of chloride to trace its movement from the atmosphere as dry- and wet-deposition through the soil zone and ultimately to the saturated zone. Typically, the CMB method assumes no mixing of groundwater with different chloride concentrations; however, because groundwater is thought to flow into Pahute Mesa from valleys north of Pahute Mesa, groundwater flow rates (i.e., underflow) and chloride concentrations from Kawich Valley and Gold Flat were carefully considered. Precipitation was measured with bulk and tipping-bucket precipitation gauges installed for this study at six sites on Pahute Mesa. These data, along with historical precipitation amounts from gauges on Pahute Mesa and estimates from the PRISM model, were evaluated to estimate mean annual precipitation. Chloride deposition from the atmosphere was estimated by analyzing quarterly samples of wet- and dry-deposition for chloride in the bulk gauges and evaluating chloride wet-deposition amounts measured at other locations by the National Atmospheric Deposition Program. Mean chloride concentrations in groundwater were estimated using data from the UGTA Geochemistry Database, data from other reports, and data from samples collected from emplacement boreholes for this study. Calculations were conducted assuming both no underflow and underflow from Kawich Valley and Gold Flat. Model results estimate recharge to be 30 mm/yr with a standard deviation of 18 mm/yr on Pahute Mesa, for elevations >1800 m amsl. These estimates assume Pahute Mesa recharge mixes completely with underflow from Kawich Valley and Gold Flat. The model assumes that precipitation, chloride concentration in bulk deposition, underflow and its chloride concentration, have been constant over the length of time of recharge.

Cooper, Clay A [DRI] [DRI; Hershey, Ronald L [DRI] [DRI; Healey, John M [DRI] [DRI; Lyles, Brad F [DRI] [DRI

2013-07-01T23:59:59.000Z

278

Situ treatment of contaminated groundwater  

DOE Green Energy (OSTI)

A system for treating dissolved halogenated organic compounds in groundwater that relies upon electrolytically-generated hydrogen to chemically reduce the halogenated compounds in the presence of a suitable catalyst. A direct current is placed across at least a pair, or an array, of electrodes which are housed within groundwater wells so that hydrogen is generated at the cathode and oxygen at the anode. A pump is located within the well housing in which the cathode(s) is(are) located and draws in groundwater where it is hydrogenated via electrolysis, passes through a well-bore treatment unit, and then transported to the anode well(s) for reinjection into the ground. The well-bore treatment involves a permeable cylinder located in the well bore and containing a packed bed of catalyst material that facilitates the reductive dehalogenation of the halogenated organic compounds by hydrogen into environmentally benign species such as ethane and methane. Also, electro-osmatic transport of contaminants toward the cathode also contributes to contaminant mass removal. The only above ground equipment required are the transfer pipes and a direct circuit power supply for the electrodes. The electrode wells in an array may be used in pairs or one anode well may be used with a plurality of cathode wells. The DC current flow between electrode wells may be periodically reversed which controls the formation of mineral deposits in the alkaline cathode well-bore water, as well as to help rejuvenate the catalysis.

McNab, Jr., Walt W. (Concord, CA); Ruiz, Roberto (Tracy, CA); Pico, Tristan M. (Livermore, CA)

2001-01-01T23:59:59.000Z

279

Stochastic Models of Shear-Flow Turbulence with Enstrophy Transfer to Subgrid Scales  

Science Conference Proceedings (OSTI)

A stochastic model for shear-flow turbulence is constructed under the constraint that the parameterized nonlinear eddy–eddy interactions conserve energy but dissipate potential enstrophy. This parameterization is appropriate for truncated models ...

Timothy DelSole

1999-11-01T23:59:59.000Z

280

Effects of Transient Eddies on Blocking Flows: General Circulation Model Experiments  

Science Conference Proceedings (OSTI)

Prediction of blocking flows by a comprehensive general circulation model is still not satisfactory. A large portion of the unskillful forecasts can be traced to the model's inability to predict the evolution of blocking beyond a few days into ...

Wilbur Y. Chen; Hann-ming Henry Juang

1992-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

A Spectral Model for Process Studies of Rotating, Density-Stratified Flows  

Science Conference Proceedings (OSTI)

A numerical model designed for three-dimensional process studies of rotating, stratified flows is described. The model is freely available, parallel, and portable across a range of computer architectures. The underlying numerics are high quality, ...

K. B. Winters; J. A. MacKinnon; Bren Mills

2004-01-01T23:59:59.000Z

282

Market power and welfare effects in DC power flow electricity models with thermal line losses  

Science Conference Proceedings (OSTI)

A nodal electric power network with Cournot-Nash interaction among power generators is formulated as a mixed complementarity problem. The model incorporates a direct current (DC) power flow approximation with thermal line losses to model real-time flows. ... Keywords: Electricity markets, Imperfect competition, Thermal line losses, Welfare measurement

Rastislav Ivanic; Paul V. Preckel; Zuwei Yu

2005-10-01T23:59:59.000Z

283

An iterative stochastic ensemble method for parameter estimation of subsurface flow models  

Science Conference Proceedings (OSTI)

Parameter estimation for subsurface flow models is an essential step for maximizing the value of numerical simulations for future prediction and the development of effective control strategies. We propose the iterative stochastic ensemble method (ISEM) ... Keywords: Iterative stochastic ensemble method, Parameter estimation, Regularization, Subsurface flow models

Ahmed H. Elsheikh, Mary F. Wheeler, Ibrahim Hoteit

2013-06-01T23:59:59.000Z

284

A heuristic method to minimise the chattering problem in dynamic mathematical two-phase flow models  

Science Conference Proceedings (OSTI)

This paper introduces the chattering problem in dynamic mathematical two-phase flow models. The real system object of study is also introduced, the DISS test facility, a parabolic-trough solar power plant using as heat transfer fluid the steam-water ... Keywords: Chattering, Heuristic methods, Modelling and simulation, Parabolic-trough solar power plant, Two-phase flow, Zeno phenomenon

J. Bonilla; L. J. Yebra; S. Dormido

2011-09-01T23:59:59.000Z

285

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

for Modeling Fluid and Heat Flow in Fractured Porous Media,with fluid and heat flow in fractured porous media arefluid and heat flow in porous media, heat pipe, reservoir simulation, fractured

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

286

Geochemistry of Delaware Basin groundwaters  

DOE Green Energy (OSTI)

Fluids from various formations were sampled and analyzed in order to characterize groundwaters in the Delaware Basin. Waters were analyzed for solute content and/or stable isotope ratios (D/H and /sup 18/O//sup 16/O). Three lines of geochemical arguments are summarized, in order to present the natures and probable origins of analyzed fluids: solute chemistry, thermodynamic modelling of low-temperature aqueous species, and stable isotope ratios. (JGB)

Lambert, S.J.

1977-04-25T23:59:59.000Z

287

Modeling Bulk Atmospheric Drainage Flow in a Valley  

Science Conference Proceedings (OSTI)

Most simulations of bulk valley-drainage flows depend heavily on parameterizations. The 1984 Atmospheric Studies in Complex Terrain (ASCOT) field experiment in Brush Creek Valley, Colorado, provided an unprecedented density of measurements in a ...

Ronald J. Dobosy

1989-09-01T23:59:59.000Z

288

Deep Planetary Circulation and Topography: Simple Models of Midocean Flows  

Science Conference Proceedings (OSTI)

The presence of broad, flowing water masses in the deep ocean requires dynamical explanation. Vertical density diffusion and?-effect are invoked in classical theories; here we show how topographic potential vorticity can control broad baroclinic ...

Peter B. Rhines

1989-10-01T23:59:59.000Z

289

Application of the pseudolinear flow model to the pressure transient analysis of fractured wells  

SciTech Connect

The theoretical basis for the pseudolinear flow model is established. It is demonstrated by using an analytical model that the linear flow graph (p vs ..sqrt..t) can be extended to the analysis of pressure data of fractured wells intersected by an intermediate or a high conductivity fracture ((k /SUB f/ b /SUB f/ greater than or equal to 15). It appears that the fracture conductivity effect during the pseudolinear flow period can be handled as a pseudo skin pressure drop which is additive to the pressure drop caused by fluid loss damage. The combination of the pseudolinear flow analysis with other interpretation techniques is illustrated through examples of field cases.

Cinco-Ley, H.; Rodriguez, F.; Samaniego, F.

1984-09-01T23:59:59.000Z

290

Comparison of calculated results from two analytical models with measured data from a heat-exchanger flow test  

SciTech Connect

Predicted results from both a network flow model and a turbulent flow model were compared with measured results from an air flow test on a half-scale model of the auxiliary heat exchanger for a high-temperature gas-cooled reactor. Measurements of both velocity and pressure were made within the heat exchanger shell side flow field. These measurements were compared with calculated results from both a network flow model and a turbulent flow model. Both analytical models predicted early identical results which, except for some minor anomalies, compared favorably with the measured data.

Carosella, D.P.; Pavlics, P.N.

1983-05-01T23:59:59.000Z

291

Observation and Modeling of the Solar-Cycle Variation of the Meridional Flow  

E-Print Network (OSTI)

We present independent observations of the solar-cycle variation of flows near the solar surface and at a depth of about 60 Mm, in the latitude range $\\pm45^\\circ$. We show that the time-varying components of the meridional flow at these two depths have opposite sign, while the time-varying components of the zonal flow are in phase. This is in agreement with previous results. We then investigate whether the observations are consistent with a theoretical model of solar-cycle dependent meridional circulation based on a flux-transport dynamo combined with a geostrophic flow caused by increased radiative loss in the active region belt (the only existing quantitative model). We find that the model and the data are in qualitative agreement, although the amplitude of the solar-cycle variation of the meridional flow at 60 Mm is underestimated by the model.

Gizon, L

2008-01-01T23:59:59.000Z

292

Observation and Modeling of the Solar-Cycle Variation of the Meridional Flow  

E-Print Network (OSTI)

We present independent observations of the solar-cycle variation of flows near the solar surface and at a depth of about 60 Mm, in the latitude range $\\pm45^\\circ$. We show that the time-varying components of the meridional flow at these two depths have opposite sign, while the time-varying components of the zonal flow are in phase. This is in agreement with previous results. We then investigate whether the observations are consistent with a theoretical model of solar-cycle dependent meridional circulation based on a flux-transport dynamo combined with a geostrophic flow caused by increased radiative loss in the active region belt (the only existing quantitative model). We find that the model and the data are in qualitative agreement, although the amplitude of the solar-cycle variation of the meridional flow at 60 Mm is underestimated by the model.

L. Gizon; M. Rempel

2008-03-06T23:59:59.000Z

293

Cooling by Heat Conduction Inside Magnetic Flux Loops and the Moderate Cluster Cooling Flow Model  

E-Print Network (OSTI)

I study non-radiative cooling of X-ray emitting gas via heat conduction along magnetic field lines inside magnetic flux loops in cooling flow clusters of galaxies. I find that such heat conduction can reduce the fraction of energy radiated in the X-ray band by a factor of 1.5-2. This non-radiative cooling joins two other proposed non-radiative cooling processes, which can be more efficient. These are mixing of cold and hot gas, and heat conduction initiated by magnetic fields reconnection between hot and cold gas. These processes when incorporated into the moderate cooling flow model lead to a general cooling flow model with the following ingredients. (1) Cooling flow does occur, but with a mass cooling rate about 10 times lower than in old versions of the cooling flow model. Namely, heating occurs such that the effective age of the cooling flow is much below the cluster age, but the heating can't prevent cooling altogether. (2) The cooling flow region is in a non-steady state evolution. (3) Non-radiative cooling of X-ray emitting gas can bring the model to a much better agreement with observations. (4) The general behavior of the cooling flow gas, and in particular the role played by magnetic fields, make the intracluster medium in cooling flow clusters similar in some aspects to the active solar corona.

Noam Soker

2003-11-02T23:59:59.000Z

294

Urban traffic flow forecasting using Gauss-SVR with cat mapping, cloud model and PSO hybrid algorithm  

Science Conference Proceedings (OSTI)

In order to improve forecasting accuracy of urban traffic flow, this paper applies support vector regression (SVR) model with Gauss loss function (namely Gauss-SVR) to forecast urban traffic flow. By using the input historical flow data as the validation ... Keywords: Cat mapping, Chaos theory, Cloud model, Particle Swarm Optimization, Support vector regression, Traffic flow forecasting

Ming-Wei Li; Wei-Chiang Hong; Hai-Gui Kang

2013-01-01T23:59:59.000Z

295

Progress in the Development of Compressible, Multiphase Flow Modeling Capability for Nuclear Reactor Flow Applications  

Science Conference Proceedings (OSTI)

In nuclear reactor safety and optimization there are key issues that rely on in-depth understanding of basic two-phase flow phenomena with heat and mass transfer. Within the context of multiphase flows, two bubble-dynamic phenomena – boiling (heterogeneous) and flashing or cavitation (homogeneous boiling), with bubble collapse, are technologically very important to nuclear reactor systems. The main difference between boiling and flashing is that bubble growth (and collapse) in boiling is inhibited by limitations on the heat transfer at the interface, whereas bubble growth (and collapse) in flashing is limited primarily by inertial effects in the surrounding liquid. The flashing process tends to be far more explosive (and implosive), and is more violent and damaging (at least in the near term) than the bubble dynamics of boiling. However, other problematic phenomena, such as crud deposition, appear to be intimately connecting with the boiling process. In reality, these two processes share many details.

R. A. Berry; R. Saurel; F. Petitpas; E. Daniel; O. Le Metayer; S. Gavrilyuk; N. Dovetta

2008-10-01T23:59:59.000Z

296

Modeling Turbulent Flow in an Urban Central Business District  

Science Conference Proceedings (OSTI)

The Realistic Urban Spread and Transport of Intrusive Contaminants (RUSTIC) model has been developed as a simplified computational fluid dynamics model with a k–? turbulence model to be used to provide moderately fast simulations of turbulent ...

Donald A. Burrows; Eric A. Hendricks; Steve R. Diehl; Robert Keith

2007-12-01T23:59:59.000Z

297

Analytical modeling of core hydraulics and flow management in breeder reactors  

SciTech Connect

An analytical model representing the hydraulic behavior of the primary system of fast breeder nuclear reactors is discussed. A computer code capable of detailing the core flow distribution and characterizing the flow and pressure drop in each reactor component is presented. Application of this method to the reactor core thermal-hydraulic design has allowed optimization of the flow management with consequent upgrading in performance, reduction of unnecessary conservatism and very substantial cost savings. Typical quantitative examples are presented.

Carelli, M.D.; Willis, J.M.

1979-01-01T23:59:59.000Z

298

Borehole Optimisation System (BOS) - A case study assessing options for abstraction of urban groundwater in Nottingham, UK  

Science Conference Proceedings (OSTI)

The recognition that urban groundwater is a potentially valuable resource for potable and industrial uses due to growing pressures on perceived less polluted rural groundwater has led to a requirement to assess the groundwater contamination risk in urban ... Keywords: Borehole Optimisation System, GIS, PCE, Probabilistic risk modelling, Urban groundwater

N. G. Tait; R. M. Davison; S. A. Leharne; D. N. Lerner

2008-05-01T23:59:59.000Z

299

A Model For The Transient Temperature Effects Of Horizontal Fluid Flow In  

Open Energy Info (EERE)

Transient Temperature Effects Of Horizontal Fluid Flow In Transient Temperature Effects Of Horizontal Fluid Flow In Geothermal Systems Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Model For The Transient Temperature Effects Of Horizontal Fluid Flow In Geothermal Systems Details Activities (1) Areas (1) Regions (0) Abstract: A characteristic temperature versus depth (T-D) profile is observed in various geothermal environments. Particular features of the T-D profile can be explained in terms of a simple time-dependent two-dimensional (x, z) hydrothermal model. In this model a hot fluid is constrained to flow along a thin aquifer buried at a depth l from the surface with conductive heat transfer into the rocks both above and below the aquifer. In many geothermal systems transient changes in the flow

300

Analyzing Unsatirated Flow Patterns in Fractured Rock Using an Integrated Modeling Approach  

Science Conference Proceedings (OSTI)

Characterizing percolation patterns in unsaturated fractured rock has posed a greater challenge to modeling investigations than comparable saturated zone studies, because of the heterogeneous nature of unsaturated media and the great number of variables impacting unsaturated flow. This paper presents an integrated modeling methodology for quantitatively characterizing percolation patterns in the unsaturated zone of Yucca Mountain, Nevada, a proposed underground repository site for storing high-level radioactive waste. The modeling approach integrates a wide variety of moisture, pneumatic, thermal, and isotopic geochemical field data into a comprehensive three-dimensional numerical model for modeling analyses. It takes into account the coupled processes of fluid and heat flow and chemical isotopic transport in Yucca Mountain's highly heterogeneous, unsaturated fractured tuffs. Modeling results are examined against different types of field-measured data and then used to evaluate different hydrogeological conceptualizations and their results of flow patterns in the unsaturated zone. In particular, this model provides a much clearer understanding of percolation patterns and flow behavior through the unsaturated zone, both crucial issues in assessing repository performance. The integrated approach for quantifying Yucca Mountain's flow system is demonstrated to provide a practical modeling tool for characterizing flow and transport processes in complex subsurface systems.

Y.S. Wu; G. Lu; K. Zhang; L. Pan; G.S. Bodvarsson

2006-08-03T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

A model for stratified gas-liquid turbulent flow in ducts of arbitrary cross-section  

E-Print Network (OSTI)

93 A model for stratified gas-liquid turbulent flow in ducts of arbitrary cross-section J. M the pressure gradient and the liquid fraction in two-phase gas- liquid fully developed stratified flow.60 Nomenclature. - TWO-PHASE VARIABLES. Definition densities statistical average (gas, liquid) mass average phase

Paris-Sud XI, Université de

302

Flow Allocation Model and Algorithm Based on Multi-target Coal Transportation Network  

Science Conference Proceedings (OSTI)

Coal transportation network consists of multiple logistics nodes and transportation paths. As the node capacity and cost factors is limited, its flow distribution is a multi-target and multi-constraint problem. Through the use of multi-target planning ... Keywords: flow allocation, model, algorithm, multi-target, coal transportation network

Tingting Zhu; Tianjun Hu; Xifu Wang; Yalong Zhao

2012-04-01T23:59:59.000Z

303

Multiple temperature kinetic model and gas-kinetic method for hypersonic non-equilibrium flow computations  

Science Conference Proceedings (OSTI)

It is well known that for increasingly rarefied flowfields, the predictions from continuum formulation, such as the Navier-Stokes equations lose accuracy. For the high speed diatomic molecular flow in the transitional regime, the inaccuracies are partially ... Keywords: Gas-kinetic method, Hypersonic and rarefied flows, Multiple temperature kinetic model

Kun Xu; Xin He; Chunpei Cai

2008-07-01T23:59:59.000Z

304

Modeling and discretization errors in large eddy simulations of hydrodynamic and magnetohydrodynamic channel flows  

Science Conference Proceedings (OSTI)

We assess the performances of three different subgrid scale models in large eddy simulations (LES) of turbulent channel flows. Two regimes are considered: hydrodynamic and magnetohydrodynamic (i.e. in the presence of a uniform wall-normal magnetic field). ... Keywords: Channel flow, Finite-volume method, Hydrodynamic, Kinetic energy budget, Large eddy simulation, Magnetohydrodynamic, Spectral method

A. Viré; D. Krasnov; T. Boeck; B. Knaepen

2011-03-01T23:59:59.000Z

305

Using Analytical and Numerical Modeling to Assess the Utility of Groundwater Monitoring Parameters at Carbon Capture, Utilization, and Storage Sites  

E-Print Network (OSTI)

://www.gettysburg.edu/academics/physics/clea/CLEAhome.html 4) Inner solar system orbital model http://donald.phast

Texas at Austin, University of

306

Groundwater chemistry at the Nevada Test Site: Data and preliminary interpretations  

SciTech Connect

The interpretation of chemical analyses of groundwater collected at and near the Nevada Test Site (NTS) has been vital in developing conceptual models of groundwater flow in the area. These conceptual models are tested using recent chemical data generated by the Desert Research Institute, as well as historic analyses from the US Geological Survey. A total of 81 wells are represented by analyses from 1957 to 1990, with generally excellent agreement between repeat samples from the same location. As identified by previous workers, three hydrochemical facies are represented by the samples: Ca-Mg-HCO{sub 3} water in carbonate rocks or alluvium derived from carbonates, Na-K-HCO{sub 3} water in volcanic rocks and alluvium derived from volcanic rocks, and a mixed fades found in many carbonate and alluvium water samples, and some volcanic waters. There is a general lack of lateral continuity in chemical characteristics along presumed flowpaths within each hydrologic unit (alluvium, carbonate, and volcanic). Though a lack of continuity between basins on the east side of the NTS was expected for water in alluvial and volcanic units due to the absence of interbasin flow, chemical differences observed within individual basins suggest a dominance of vertical over lateral flow. Groundwater in volcanic materials on the east side of Yucca and Frenchman Flats and on the west side of Pahute Mesa and Yucca Mountain has a nearly pure Na-K-HCO{sub 3} signature that reflects contact with primarily volcanic material. Groundwater in volcanic units in the middle of the NTS and on the east side of Pahute Mesa contains a higher proportion of Ca, Mg, Cl, and SO{sub 4} than the other volcanic waters and indicates the contribution of water from the upper carbonate aquifer and/or hydrothermally altered regions.

Chapman, J.B.; Lyles, B.F.

1993-03-01T23:59:59.000Z

307

Analyzing flow patterns in unsaturated fractured rock of YuccaMountain using an integrated modeling approach  

SciTech Connect

This paper presents a series of modeling investigations to characterize percolation patterns in the unsaturated zone of Yucca Mountain, Nevada, a proposed underground repository site for storing high-level radioactive waste. The investigations are conducted using a modeling approach that integrates a wide variety of moisture, pneumatic, thermal, and isotopic geochemical field data into a comprehensive three-dimensional numerical model through model calibration. This integrated modeling approach, based on a dual-continuum formulation, takes into account the coupled processes of fluid and heat flow and chemical isotopic transport in Yucca Mountain's highly heterogeneous, unsaturated fractured tuffs. In particular, the model results are examined against different types of field-measured data and used to evaluate different hydrogeological conceptual models and their effects on flow patterns in the unsaturated zone. The objective of this work to provide understanding of percolation patterns and flow behavior through the unsaturated zone, which is a crucial issue in assessing repository performance.

Wu, Yu-Shu; Lu, Guoping; Zhang, Keni; Pan, Lehua; Bodvarsson,Gudmundur S.

2003-11-03T23:59:59.000Z

308

Turbulent Flow Analysis and Coherent Structure Identification in Experimental Models with Complex Geometries  

E-Print Network (OSTI)

Turbulent flows and coherent structures emerging within turbulent flow fields have been extensively studied for the past few decades and a wide variety of experimental and numerical techniques have been developed for measurement and analysis of turbulent flows. The complex nature of turbulence requires methods that can accurately estimate its highly chaotic spatial and temporal behavior. Some of the classical cases of turbulent flows with simpler geometries have been well characterized by means of the existing experimental techniques and numerical models. Nevertheless, since most turbulent fields are of complex geometries; there is an increasing interest in the study of turbulent flows through models with more complicated geometries. In this dissertation, characteristics of turbulent flows through two different facilities with complex geometries are studied applying two different experimental methods. The first study involves the investigation of turbulent impinging jets through a staggered array of rods with or without crossflow. Such flows are crucial in various engineering disciplines. This experiment aimed at modeling the coolant flow behavior and mixing phenomena within the lower plenum of a Very High Temperature Reactor (VHTR). Dynamic Particle Image Velocimetry (PIV) and Matched Index of Refraction (MIR) techniques were applied to acquire the turbulent velocity fields within the model. Some key flow features that may significantly enhance the flow mixing within the test section or actively affect some of the structural components were identified in the velocity fields. The evolution of coherent structures within the flow field is further investigated using a Snapshot Proper Orthogonal Decomposition (POD) technique. Furthermore, a comparative POD method is proposed and successfully implemented for identification of the smaller but highly influential coherent structures which may not be captured in the full-field POD analysis. The second experimental study portrays the coolant flow through the core of an annular pebble bed VHTR. The complex geometry of the core and the highly turbulent nature of the coolant flow passing through the gaps of fuel pebbles make this case quite challenging. In this experiment, a high frequency Hot Wire Anemometry (HWA) system is applied for velocity measurements and investigation of the bypass flow phenomena within the near wall gaps of the core. The velocity profiles within the gaps verify the presence of an area of increased velocity close to the outer reflector wall; however, the characteristics of the coolant flow profile is highly dependent on the gap geometry and to a less extent on the Reynolds number of the flow. The time histories of the velocity are further analyzed using a Power Spectra Density (PSD) technique to acquire information about the energy content and energy transfer between eddies of different sizes at each point within the gaps.

Amini, Noushin

2011-12-01T23:59:59.000Z

309

Impulsively Started Flow in a Submarine Canyon: Comparison of Results from Laboratory and Numerical Models  

Science Conference Proceedings (OSTI)

Intercomparisons have been made of results from laboratory experiments and a numerical model for the flow in the vicinity of an idealized submarine canyon located along an otherwise continuous shelf. Motion in the rotating and continuously ...

Nicolas Pérenne; J. William Lavelle; David C. Smith IV; Don L. Boyer

2001-10-01T23:59:59.000Z

310

The Interaction of Katabatic Flow and Mountain Waves. Part II: Case Study Analysis and Conceptual Model  

Science Conference Proceedings (OSTI)

Via numerical analysis of detailed simulations of an early September 1993 case night, the authors develop a conceptual model of the interaction of katabatic flow in the nocturnal boundary layer with mountain waves (MKI). A companion paper (Part I)...

Gregory S. Poulos; James E. Bossert; Thomas B. McKee; Roger A. Pielke Sr.

2007-06-01T23:59:59.000Z

311

Rheo-PIV Analysis of the Yielding and Flow of Model Waxy Crude Oils  

E-Print Network (OSTI)

Waxes are a commonly encountered precipitate that can result in the gelation of crude oils and cessation of flow in pipelines. In this work, we develop a model wax–oil system that exhibits rheological behavior similar to ...

Dimitriou, Christopher J.

312

Pore-scale modeling of immiscible and miscible fluid flows using smoothed particle hydrodynamics  

Science Conference Proceedings (OSTI)

A numerical model based on smoothed particle hydrodynamics (SPH) was developed and used to simulate immiscible and miscible fluid flows in porous media and to study effects of porous scale heterogeneity and anisotropy on such flows. Models for heterogeneous porous media were generated by using randomly located non-intersecting circular grains of different sizes, and pore scale anisotropy was introduced by randomly inserting non-overlapping particles on either side of the gap between two self-affine fractal curves to create a microfracture. . Different fluid wetting behaviors and surface tensions were modeled using pairwise particle-particle interactions. Particles with different masses and viscosities were used to model multiphase flow. In simulations of miscible fluid flow, particles with variable, composition dependent, masses and viscosities were used. Artificial surface tension effects were avoided by basing the SPH equations on the particle number density.

Tartakovsky, Alexandre M.; Meakin, Paul

2006-10-31T23:59:59.000Z

313

Evolving Multisensor Precipitation Estimation Methods: Their Impacts on Flow Prediction Using a Distributed Hydrologic Model  

Science Conference Proceedings (OSTI)

This study investigates evolving methodologies for radar and merged gauge–radar quantitative precipitation estimation (QPE) to determine their influence on the flow predictions of a distributed hydrologic model. These methods include the National ...

David Kitzmiller; Suzanne Van Cooten; Feng Ding; Kenneth Howard; Carrie Langston; Jian Zhang; Heather Moser; Yu Zhang; Jonathan J. Gourley; Dongsoo Kim; David Riley

2011-12-01T23:59:59.000Z

314

The Principles of Laboratory Modeling of Stratified Atmospheric Flows over Complex Terrain  

Science Conference Proceedings (OSTI)

Laboratory modeling provides a reasonably quick and relatively inexpensive method for investigating stratified air Row around mesoscale topography. Quantitative results for stratified flow over complex terrain may be obtained from suitably ...

Peter G. Baines; Peter C. Manins

1989-11-01T23:59:59.000Z

315

A Numerical Modeling Study of Warm Offshore Flow over Cool Water  

Science Conference Proceedings (OSTI)

Numerical simulations of boundary layer evolution in offshore flow of warm air over cool water are conducted and compared with aircraft observations of mean and turbulent fields made at Duck, North Carolina. Two models are used: a two-dimensional,...

Eric D. Skyllingstad; Roger M. Samelson; Larry Mahrt; Phil Barbour

2005-02-01T23:59:59.000Z

316

A Numerical Model Study of Nocturnal Drainage Flows with Strong Wind and Temperature Gradients  

Science Conference Proceedings (OSTI)

A second-moment turbulence-closure model described in Yamada and Bunker is used to simulate nocturnal drainage flows observed during the 1984 ASCOT field expedition in Brush Creek, Colorado. In order to simulate the observed strong wind ...

T. Yamada; S. Bunker

1989-07-01T23:59:59.000Z

317

The Semigeostrophic Weir: A Simple Model Of Flow over Mountain Barriers  

Science Conference Proceedings (OSTI)

Conventional inviscid theories of flow over smooth orography assume that boundary streamlines do not separate and that, for steady solutions, the orographic surface is isentropic. Cullen et al. describe an element model based on the Lagrangian ...

G. J. Shutts

1987-08-01T23:59:59.000Z

318

Use of a Mixed-Layer Model to Investigate Problems in Operational Prediction of Return Flow  

Science Conference Proceedings (OSTI)

Inaccuracy in the numerical prediction of the moisture content of return-flow air over the Gulf of Mexico continues to plague operational forecasters. At the Environmental Modeling Center/National Centers for Environmental Prediction in the ...

John M. Lewis

2007-07-01T23:59:59.000Z

319

A flow modeling of lubricating greases under shear deformation by cellular automata  

Science Conference Proceedings (OSTI)

A Cellular Automata modeling of the lubricating grease flow under the shear deformation is proposed Lubricating greases are composed of thickening agent, liquid lubricant and various kinds of additives The thickening agent forms fibrous microstructures ...

Shunsuke Miyamoto; Hideyuki Sakai; Toshihiko Shiraishi; Shin Morishita

2006-09-01T23:59:59.000Z

320

Explicit Filtering and Reconstruction Turbulence Modeling for Large-Eddy Simulation of Neutral Boundary Layer Flow  

Science Conference Proceedings (OSTI)

Standard turbulence closures for large-eddy simulations of atmospheric flow based on finite-difference or finite-volume codes use eddy-viscosity models and hence ignore the contribution of the resolved subfilter-scale stresses. These eddy-...

Fotini Katopodes Chow; Robert L. Street; Ming Xue; Joel H. Ferziger

2005-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Symmetry Methods for a Geophysical Mass Flow Model  

Science Conference Proceedings (OSTI)

In the framework of symmetry analysis, the class of 2 x 2 PDE systems to whom belong the Savage and Hutter model and the Iverson model is considered. New classes of exact solutions are found.

Torrisi, Mariano; Tracina, Rita [Dipartimento di Matematica e Informatica, Viale A. Doria 6, Catania (Italy)

2011-09-14T23:59:59.000Z

322

A Quasi-equilibrium Turbulent Energy Model for Geophysical Flows  

Science Conference Proceedings (OSTI)

The Mellor-Yamada hierarchy of turbulent closure models is reexamined to show that the elimination of a slight inconsistency in their analysis leads to a quasi-equilibrium model that is somewhat simpler than their level 2½ model. Also the need to ...

B. Galperin; L. H. Kantha; S. Hassid; A. Rosati

1988-01-01T23:59:59.000Z

323

Bioremediation of contaminated groundwater  

DOE Patents (OSTI)

The present invention relates to a method for in situ bioremediation of contaminated soil and groundwater. In particular, the invention relates to remediation of contaminated soil and groundwater by the injection of nutrients to stimulate growth of pollutant-degrading microorganisms. The United States Government has rights in this invention pursuant to Contract No. DE-AC09-89SR18035 between the US Department of Energy and Westinghouse Savannah River Company.

Hazen, T.C.; Fliermans, C.B.

1992-12-31T23:59:59.000Z

324

On the subcooled critical flow model in RELAP5/MOD3  

SciTech Connect

An analysis of an anomaly in the subcooled critical flow model in the RELAP5/MOD3 computer code is presented. Specifically, the code produces a discontinuity in going from unchoked subcooled liquid flow (i.e., subsonic flow) to subcooled choked flow (i.e., sonic flow). The same anomaly has been reported elsewhere. The root cause for this anomaly has been analyzed, and it is found that the user-supplied junction loss coefficient and discharge coefficient play an important role in the occurrence of this anomaly. The analysis is verified by assessment against a test problem simulating single-phase liquid flow through a convergent nozzle with a fixed upstream pressure and a varying downstream pressure. A corrective measure to eliminate the discontinuity is suggested.

Yeung, W.S.; Shirkov, J. [Yankee Atomic Electric Co., Bolton, MA (United States)

1996-04-01T23:59:59.000Z

325

Modelling Surface Flows for Macroscopic Phenomena by Cellular Automata: An Application to Debris Flows  

Science Conference Proceedings (OSTI)

Cellular automata are good candidates for modelling and simulating complex dynamical systems, whose evolution depends on the local interactions of their constituent parts. Many macroscopic phenomena have such features, but their complexity involves sometime ...

Donato D'Ambrosio; Salvatore Di Gregorio; Giulio Iovine; Valeria Lupiano; Rocco Rongo; William Spataro

2002-10-01T23:59:59.000Z

326

Triangular flow in heavy ion collisions in a multiphase transport model  

E-Print Network (OSTI)

We obtain a new set of parameters in a multiphase transport (AMPT) model that are able to describe both the charged particle multiplicity density and the elliptic flow measured in Au + Au collisions at center-of-mass energy root(S)NN = 200 GeV at the Relativistic Heavy Ion Collider, although they still give somewhat softer transverse momentum spectra. We then use the model to predict the triangular flow due to fluctuations in the initial collision geometry and study its effect relative to those from other harmonic components of anisotropic flows on the dihadron azimuthal correlations in both central and midcentral collisions.

Xu, Jun; Ko, Che Ming.

2011-01-01T23:59:59.000Z

327

Definition: Groundwater Sampling | Open Energy Information  

Open Energy Info (EERE)

Dictionary.png Groundwater Sampling Groundwater sampling is done to characterize the chemical, thermal, or hydrological properties of subsurface aqueous systems. Groundwater...

328

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

grain-specific heat for each model grid layer, are providedand heat flow is simulated using the 3-D TH model grid (

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

329

Cold flow modeling of pulverized coal combustors for magnetohydrodynamic channel applications  

DOE Green Energy (OSTI)

This report describes an experimental program and techniques for studying the internal aerodynamics of pulverized coal combustors of the type used in magnetohydrodynamic test trains at The University of Tennessee Space Institute. The combustors are modeled with small scale, cold flow models that permit both flow visualization and velocity field surveys to be performed. Water was selected as the working fluid so that the model flow fields had the same Reynolds number as the actual reactive combustors, and also to facilitate flow visualization. The systems used for flow visualization and velocity field surveying are described in detail. The velocity field survey equipment is based on a vector-velocity, laser doppler velocimeter coupled to a controllable field scanning device and a microprocessor for on-line data reduction. Results are presented that were obtained from a laser velocimeter study of recirculating flows in a combustor model. The results show that, even for exceedingly simple geometrical arrangements of oxidant injector configurations, complex three dimensional highly turbulent flow fields exist in the combustor. A brief discussion of the impact of the results on fuel injector positioning is presented.

Schulz, R.J.; Giel, T.V.; Ghosh, A.; Morris, R.D.

1984-03-01T23:59:59.000Z

330

Model Reduction for Control of Stratified Flows in Buildings  

NLE Websites -- All DOE Office Websites (Extended Search)

models, widely used in whole building simulation tools, are inadequate for capturing thermal stratification that typically arises while using passive, low-energy, heating and...

331

Numerical modeling of the wind flow over a transverse dune  

E-Print Network (OSTI)

Transverse dunes, which form under unidirectional winds and have fixed profile in the direction perpendicular to the wind, occur on all celestial objects of our solar system where dunes have been detected. Here we perform a numerical study of the average turbulent wind flow over a transverse dune by means of computational fluid dynamics simulations. We find that the length of the zone of recirculating flow at the dune lee --- the {\\em{separation bubble}} --- displays a surprisingly strong dependence on the wind shear velocity, $u_{\\ast}$: it is nearly independent of $u_{\\ast}$ for shear velocities within the range between $0.2\\,$m$$s and $0.8\\,$m$$s but increases linearly with $u_{\\ast}$ for larger shear velocities. Our calculations show that transport in the direction opposite to dune migration within the separation bubble can be sustained if $u_{\\ast}$ is larger than approximately $0.39\\,$m$$s, whereas a larger value of $u_{\\ast}$ (about $0.49\\,$m$$s) is required to initiate this reverse transport.

Ascânio D. Araújo; Eric J. R. Parteli; Thorsten Poeschel; José S. Andrade Jr.; Hans J. Herrmann

2013-07-26T23:59:59.000Z

332

Non-equilibrium effects and multiphase flow in porous media.  

E-Print Network (OSTI)

??We encounter flow in porous media, knowingly or otherwise, on a daily basis; percolation of precipitation into top soil, ground-water supplies obtained from aquifers (ground-water… (more)

Aryana, Saman Afqahi.

2012-01-01T23:59:59.000Z

333

New Heat Flow Models in Fractured Geothermal Reservoirs - Final Report  

DOE Green Energy (OSTI)

This study developed new analytical models for predicting the temperature distribution within a geothermal reservoir following reinjection of water having a temperature different from that of the reservoir. The study consisted of two parts: developing new analytical models for the heat conduction rate into multi-dimensional, parallelepiped matrix blocks and developing new analytical models for the advance of the thermal front through the geothermal reservoir. In the first part of the study, a number of semi-empirical models for the multi-dimensional heat conduction were developed to overcome the limitations to the exact solutions. The exact solution based on a similarity solution to the heat diffusion equation is the best model for the early-time period, but fails when thermal conduction fronts from opposing sides of the matrix block merge. The exact solution based on an infinite series solution was found not to be useful because it required tens of thousands of terms to be include d for accuracy. The best overall model for the entire conduction time was a semi-empirical model based on an exponential conduction rate. In the second part of the study, the early-time period exact solution based on similarity methods and the semi-empirical exponential model were used to develop new analytical models for the location of the thermal front within the reservoir during injection. These equations were based on an energy balance on the water in the fractured network. These convective models allowed for both dual and triple porosity reservoirs, i.e., one or two independent matrix domains. A method for incorporating measured fracture spacing distributions into these convective models was developed. It was found that there were only minor differences in the predicted areal extent of the heated zone between the dual and triple porosity models. Because of its simplicity, the dual porosity model is recommended. These new models can be used for preliminary reservoir studies. Although they are not as accurate as numerical simulators, they are simple, easy and inexpensive to use. These new models can be used to get general information about reservoir behavior before committing to the considerable greater expense of numerical simulation.

Reis, John

2001-03-31T23:59:59.000Z

334

NETL: Releases & Briefs - MFIX: Particle-fluid flow modeling, fast and free  

NLE Websites -- All DOE Office Websites (Extended Search)

MFIX: Particle-fluid Flow Modeling, Fast and Free MFIX: Particle-fluid Flow Modeling, Fast and Free Until recently, full solution of the complex set of equations that describe gas-particle flows was nearly impossible. But an open-source code developed by researchers at the National Energy Technology Laboratory (NETL), and designed to run on inexpensive PC (Beowulf) clusters, makes it relatively simple. Called MFIX (Multi-phase Flow with Interphase eXchange), the code incorporates special numerical techniques that provide an efficient solution to the coupled equations, exceeding the capabilities of commercial software. Originally developed at NETL to model fixed, fluidized and bubbling coal gasification technologies, its power has been used in research ranging from catalytic cracking in oil refineries to volcanology. A free, fully-functional version is available at www.mfix.org

335

A Numerical Model For The Dynamics Of Pyroclastic Flows At Galeras Volcano,  

Open Energy Info (EERE)

For The Dynamics Of Pyroclastic Flows At Galeras Volcano, For The Dynamics Of Pyroclastic Flows At Galeras Volcano, Colombia Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Numerical Model For The Dynamics Of Pyroclastic Flows At Galeras Volcano, Colombia Details Activities (0) Areas (0) Regions (0) Abstract: This paper presents a two-dimensional model for dilute pyroclastic flow dynamics that uses the compressible Navier-Stokes equation coupled with the Diffusion-Convection equation to take into account sedimentation. The model is applied to one of the slopes of Galeras Volcano to show: (1) the temperature evolution with the time; (2) dynamic pressure change; and (3) particle concentration along the computer domain from the eruption to the impact with a topographic barrier located more than 16 km

336

Estimation of unsaturated zone traveltimes for Rainier Mesa and Shoshone Mountain, Nevada Test Site, Nevada, using a source-responsive preferential-flow model  

SciTech Connect

Traveltimes for contaminant transport by water from a point in the unsaturated zone to the saturated zone are a concern at Rainier Mesa and Shoshone Mountain in the Nevada Test Site, Nevada. Where nuclear tests were conducted in the unsaturated zone, contaminants must traverse hundreds of meters of variably saturated rock before they enter the saturated zone in the carbonate rock, where the regional groundwater system has the potential to carry them substantial distances to a location of concern. The unsaturated-zone portion of the contaminant transport path may cause a significant delay, in addition to the time required to travel within the saturated zone, and thus may be important in the overall evaluation of the potential hazard from contamination. Downward contaminant transport through the unsaturated zone occurs through various processes and pathways; this can lead to a broad distribution of contaminant traveltimes, including exceedingly slow and unexpectedly fast extremes. Though the bulk of mobile contaminant arrives between the time-scale end members, the fastest contaminant transport speed, in other words the speed determined by the combination of possible processes and pathways that would bring a measureable quantity of contaminant to the aquifer in the shortest time, carries particular regulatory significance because of its relevance in formulating the most conservative hazard-prevention scenarios. Unsaturated-zone flow is usually modeled as a diffusive process responding to gravity and pressure gradients as mediated by the unsaturated hydraulic properties of the materials traversed. The mathematical formulation of the diffuse-flow concept is known as Richards' equation, which when coupled to a solute transport equation, such as the advection-dispersion equation, provides a framework to simulate contaminant migration in the unsaturated zone. In recent decades awareness has increased that much fluid flow and contaminant transport within the unsaturated zone takes place as preferential flow, faster than would be predicted by the coupled Richards' and advection-dispersion equations with hydraulic properties estimated by traditional means. At present the hydrologic community has not achieved consensus as to whether a modification of Richards' equation, or a fundamentally different formulation, would best quantify preferential flow. Where the fastest contaminant transport speed is what needs to be estimated, there is the possibility of simplification of the evaluation process. One way of doing so is by a two-step process in which the first step is to evaluate whether significant preferential flow and solute transport is possible for the media and conditions of concern. The second step is to carry out (a) a basic Richards' and advection-dispersion equation analysis if it is concluded that preferential flow is not possible or (b) an analysis that considers only the fastest possible preferential-flow processes, if preferential flow is possible. For the preferential-flow situation, a recently published model describable as a Source-Responsive Preferential-Flow (SRPF) model is an easily applied option. This report documents the application of this two-step process to flow through the thick unsaturated zones of Rainier Mesa and Shoshone Mountain in the Nevada Test Site. Application of the SRPF model involves distinguishing between continuous and intermittent water supply to preferential flow paths. At Rainier Mesa and Shoshone Mountain this issue is complicated by the fact that contaminant travel begins at a location deep in the subsurface, where there may be perched water that may or may not act like a continuous supply, depending on such features as the connectedness of fractures and the nature of impeding layers. We have treated this situation by hypothesizing both continuous and intermittent scenarios for contaminant transport to the carbonate aquifer and reporting estimation of the fastest speed for both of these end members.

Brian A. Ebel; John R. Nimmo

2009-09-11T23:59:59.000Z

337

DEVELOPMENT AND VALIDATION OF A MULTIFIELD MODEL OF CHURN-TURBULENT GAS/LIQUID FLOWS  

DOE Green Energy (OSTI)

The accuracy of numerical predictions for gas/liquid two-phase flows using Computational Multiphase Fluid Dynamics (CMFD) methods strongly depends on the formulation of models governing the interaction between the continuous liquid field and bubbles of different sizes. The purpose of this paper is to develop, test and validate a multifield model of adiabatic gas/liquid flows at intermediate gas concentrations (e.g., churn-turbulent flow regime), in which multiple-size bubbles are divided into a specified number of groups, each representing a prescribed range of sizes. The proposed modeling concept uses transport equations for the continuous liquid field and for each bubble field. The overall model has been implemented in the NPHASE-CMFD computer code. The results of NPHASE-CMFD simulations have been validated against the experimental data from the TOPFLOW test facility. Also, a parametric analysis on the effect of various modeling assumptions has been performed.

Elena A. Tselishcheva; Steven P. Antal; Michael Z. Podowski; Donna Post Guillen

2009-07-01T23:59:59.000Z

338

An Integrated Modeling Analysis of Unsaturated Flow Patterns inFractured Rock  

Science Conference Proceedings (OSTI)

Characterizing percolation patterns in unsaturated zones hasposed a greater challenge to numerical modeling investigations thancomparable saturated zone studies, because of the heterogeneous nature ofunsaturated media as well as the great number of variables impactingunsaturated zone flow. This paper presents an integrated modelingmethodology for quantitatively characterizing percolation patterns in theunsaturated zone of Yucca Mountain, Nevada, a proposed undergroundrepository site for storing high-level radioactive waste. It takes intoaccount the multiple coupled processes of air, water, heat flow andchemical isotopic transport in Yucca Mountain s highly heterogeneous,unsaturated fractured tuffs. The modeling approach integrates a widevariety of moisture, pneumatic, thermal, and isotopic geochemical fielddata into a comprehensive three-dimensional numerical model for modelinganalyses. Modeling results are examined against different types offield-measured data and then used to evaluate different hydrogeologicalconceptual models and their results of flow patterns in the unsaturatedzone. In particular, this integration model provides a much clearerunderstanding of percolation patterns and flow behavior through theunsaturated zone, both crucial issues in assessing repositoryperformance. The integrated approach for quantifying Yucca Mountain sflow system is also demonstrated to provide a comprehensive modeling toolfor characterizing flow and transport processes in complex subsurfacesystems.

Wu, Yu-Shu; Lu, Guoping; Zhang, Keni; Pan, Lehua; Bodvarsson,Gudmundur S.

2005-03-21T23:59:59.000Z

339

EPRI Power Flow to CIM Interface: Development of Power Flow to Common Information Model (CIM) Converter  

Science Conference Proceedings (OSTI)

IEEE has developed a Power Systems Application Data Dictionary (PSADD) for power system data and EPRI sponsored development of a CONVERTER program to convert PTI's PSS/E's data into this format. This project will develop the common data sources (CDSs) that translate the PSADD data to/from a Common Information Model (CIM)-structured database.

2002-11-27T23:59:59.000Z

340

Development of a model to predict flow oscillations in low-flow sodium boiling. [Loss-of-Piping Integrity accidents  

Science Conference Proceedings (OSTI)

Tests performed in a small scale water loop showed that voiding oscillations, similar to those observed in sodium, were present in water, as well. An analytical model, appropriate for either sodium or water, was developed and used to describe the water flow behavior. The experimental results indicate that water can be successfully employed as a sodium simulant, and further, that the condensation heat transfer coefficient varies significantly during the growth and collapse of vapor slugs during oscillations. It is this variation, combined with the temperature profile of the unheated zone above the heat source, which determines the oscillatory behavior of the system. The analytical program has produced a model which qualitatively does a good job in predicting the flow behavior in the wake experiment. The amplitude discrepancies are attributable to experimental uncertainties and model inadequacies. Several parameters (heat transfer coefficient, unheated zone temperature profile, mixing between hot and cold fluids during oscillations) are set by the user. Criteria for the comparison of water and sodium experiments have been developed.

Levin, A.E.; Griffith, P.

1980-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
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341

Modelling Shear Flows with SPH and Grid Based Methods  

E-Print Network (OSTI)

Given the importance of shear flows for astrophysical gas dynamics, we study the evolution of the Kelvin-Helmholtz instability (KHI) analytically and numerically. We derive the dispersion relation for the two-dimensional KHI including viscous dissipation. The resulting expression for the growth rate is then used to estimate the intrinsic viscosity of four numerical schemes depending on code-specific as well as on physical parameters. Our set of numerical schemes includes the Tree-SPH code VINE, an alternative SPH formulation developed by Price (2008), and the finite-volume grid codes FLASH and PLUTO. In the first part, we explicitly demonstrate the effect of dissipation-inhibiting mechanisms such as the Balsara viscosity on the evolution of the KHI. With VINE, increasing density contrasts lead to a continuously increasing suppression of the KHI (with complete suppression from a contrast of 6:1 or higher). The alternative SPH formulation including an artificial thermal conductivity reproduces the analytically ...

Junk, Veronika; Heitsch, Fabian; Burkert, Andreas; Wetzstein, Markus; Schartmann, Marc; Price, Daniel

2010-01-01T23:59:59.000Z

342

Integrated models of distribution transformers and their loads for three-phase power flow analyses  

Science Conference Proceedings (OSTI)

This paper introduces integrated models of distribution transformers and their loads for three-phase power flow analyses. All transformer connections can be easily included, such as single-phase, open wye, open delta and three-phase. For an existing three-phase power flow program without rigorous transformer models, only a slight modification of this program is needed to analyze distribution systems in more detail by using these proposed models. For those with rigorous transformer models, the rigorous transformer models usually make the program converge with difficulty, or even diverge. The convergence characteristics of these program can be dramatically improved if proposed integrated models are used instead of the rigorous transformer models. Moreover, these models can be easily applied by some functions of advanced distribution management systems or automatic mapping and facility management systems, such as transformer load management and feeder load management, to evaluate the individual phase loads along a feeder.

Chen, T.H.; Chang, Y.L. [National Taiwan Inst. of Tech., Taipei (Taiwan, Province of China). Dept. of Electrical Engineering

1996-01-01T23:59:59.000Z

343

Groundwater Sampling | Open Energy Information  

Open Energy Info (EERE)

Groundwater Sampling Groundwater Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Groundwater Sampling Details Activities (3) Areas (2) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Water Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Water composition and source of fluids. Determination of mixing ratios between different fluid end-members. Determination of fluid recharge rates and residence times. Thermal: Water temperature. Dictionary.png Groundwater Sampling: Groundwater sampling is done to characterize the chemical, thermal, or hydrological properties of subsurface aqueous systems. Groundwater sampling

344

Dynamical Modeling of Flow in Cumulus-Filled Boundary Layers  

Science Conference Proceedings (OSTI)

A primitive equation planetary boundary layer (PBL) model is constructed and applied to simulate the downwind evolution of coupled dynamic, thermodynamic and cloud properties in the PBL over warmer mean. A multilayered approach is adopted to ...

Chiu-Wai Yuen

1985-01-01T23:59:59.000Z

345

Impact of relative permeability models on fluid flow behavior for gas condensate reservoirs  

E-Print Network (OSTI)

Accurate assessments of reserves and evaluation of productivity trends for gas condensate systems depend on a basic understanding of phase and fluid flow behavior. In gas condensate reservoirs, the gas flow depends on liquid drop out at pressures below the dewpoint pressure. The liquid initially accumulates as a continuous film along the porous media because of the low interfacial tension. Then, as the volume of condensate increases, the interfacial tension increases and capillary forces become more important. Modeling fluid flow in these systems must consider the dependence of relative permeability on both viscous and capillary forces. This research focuses on the evaluation of several recently proposed relative permeability models and on the quantification of their impact on reservoir fluid flow and well performance. We selected three relative permeability models to compare the results obtained in the modeling of relative permeabilities for a published North Sea gas condensate reservoir. The models employ weighting factors to account for the interpolation between miscible and immiscible flow behavior. The Pusch model evaluated using Fevang's weighting factor gave the best estimation of relative permeability when compared to the published data. Using a sector model, we evaluated the effects at the field scale of the selected gas condensate relative permeability models on well performance under different geological heterogeneity and permeability anisotropy scenarios. The Bette and Pusch models as well as the Danesh model, as implemented in a commercial reservoir simulator, were used to quantify the impact of the relative permeability models on fluid-flow and well performance. The results showed that, if the transition between miscible and immiscible behavior is not considered, the condensate saturation could be overestimated and the condensate production could be underestimated. After twenty years of production, the heterogeneous model using the selected relative permeability models predicted between 7.5 - 13% more condensate recovery than was estimated using an immiscible relative permeability model. Using the same relative permeability models, the anisotropic model forecast between 3 - 10% more condensate recovery than predicted using an immiscible relative permeability model. Results using the anisotropic model showed that vertical communication could affect the liquid distribution in the reservoir.

Zapata Arango, Jose? Francisco

2002-01-01T23:59:59.000Z

346

Steady-state power flow modeling for a dynamic voltage restorer  

Science Conference Proceedings (OSTI)

This paper presents analysis, modeling and simulation of power distribution network performance incorporating with an installed dynamic voltage restorer (DVR). DVR is one of series compensators used in power distribution systems in order to maintain ... Keywords: Gauss-Seidel method, dynamic voltage restorer, modeling, power flow, simulation

T. Ratniyomchai; T. Kulworawanichpong

2006-03-01T23:59:59.000Z

347

Numerical Early Warning Model Research of Landfill Gas Permeation and Diffusion Considering Flow-Temperature Coupling  

Science Conference Proceedings (OSTI)

Based on seepage mechanics in porous medium gas and heat transfer theory, numerical early warning model is established, which is on quantitative description of migration and release of landfill gas and penetration and diffusion of energy, and dynamic ... Keywords: component, landfill gas, flow-temperature coupling, gas pressure and temperature distribution, numerical early warning model

Xue Qiang; Feng Xia-ting; Ma Shi-jin; Zhou Xiao-jun

2009-10-01T23:59:59.000Z

348

Density Currents in Shear Flows-A Two-Fluid Model  

Science Conference Proceedings (OSTI)

This paper develops a two-fluid steady-state model of a density current and its front propagating into a uniformly sheared environmental flow. This model is used to examine the kinematic and dynamic factors that control the depth and propagation ...

Qin Xu

1992-03-01T23:59:59.000Z

349

A stochastic multiscale framework for modeling flow through random heterogeneous porous media  

Science Conference Proceedings (OSTI)

Flow through porous media is ubiquitous, occurring from large geological scales down to the microscopic scales. Several critical engineering phenomena like contaminant spread, nuclear waste disposal and oil recovery rely on accurate analysis and prediction ... Keywords: Collocation methods, Data-driven modeling, Manifold learning, Mixed finite elements, Non-linear model reduction, Scalable algorithms, Sparse grids, Stochastic partial differential equations, Variational multiscale methods

B. Ganapathysubramanian; N. Zabaras

2009-01-01T23:59:59.000Z

350

Stratospheric Flow during Two Recent Winters Simulated by a Mechanistic Model  

Science Conference Proceedings (OSTI)

The authors have used a spectral, primitive equation mechanistic model of the stratosphere and mesosphere to simulate observed stratospheric flow through the winters of 1991–92 and 1994–95 by forcing the model at 100 hPa with observed ...

Philip W. Mote; Peter A. Stott; Robert S. Harwood

1998-06-01T23:59:59.000Z

351

Investigation of groundwater recirculation for the removal of RDX from the Pantex Plant perched aquifer  

SciTech Connect

The Pantex Plant near Amarillo, Texas, is a US Department of Energy (DOE) facility that has been in operation since 1942. Past and present operations at Pantex include the creation of chemical high explosives components for nuclear weapons and assembly and disassembly of nuclear weapons. The Pantex Plant is underlain by the Ogallala aquifer, which in this area, consists of the main water-bearing unit and a perched water zone. These are separated by a fine-grained zone of low permeability. Multiple contaminant plumes containing high explosive (HE) compounds have been detected in the perched aquifer beneath the plant. The occurrence of these contaminants is the result of past waste disposal practices at the facility. RDX is an HE compound, which has been detected in the groundwater of the perched aquifer at significant concentrations. A pilot-scale, dual-phase extraction treatment system has been installed at one location at the plant, east of Zone 12, to test the effectiveness of such a system on the removal of these contaminants from the subsurface. A tracer test using a conservative tracer, bromide (Br), was conducted at the treatment site in 1996. In addition to the bromide, RDX and water elevations in the aquifer were monitored. Using data from the tracer test and other relevant data from the investigations at Pantex, flow and contaminant transport in the perched aquifer were simulated with groundwater models. The flow was modeled using MODFLOW and the transport of contaminants in the aqueous phase was modeled using MT3D. Modeling the perched aquifer had been conducted to characterize the flow in the perched aquifer; estimate RDX retardation in the perched aquifer; and evaluate the use of groundwater re-circulation to enhance the extraction of RDX from the perched aquifer.

Woods, A.L. [ed.; Barnes, D.L. [Amarillo National Resource Center for Plutonium, TX (United States); Boles, K.M.; Charbeneau, R.J. [Univ. of Texas, Austin, TX (United States); Black, S.; Rainwater, K. [Texas Tech Univ., Lubbock, TX (United States). Water Resources Center

1998-07-01T23:59:59.000Z

352

Application of the pseudolinear-flow model to the pressure-transient analysis of fractured wells  

SciTech Connect

The theoretical basis for the pseudolinear-flow model is established. In this paper it is demonstrated by use of an analytical model that the linear-flow graph (rho vs. {Lambda}tau) can be extended to the analysis of pressure data of fractured wells intersected by an intermediate- or high-conductivity fracture (C/sub fD/ > 5{pi}). It appears that the fracture-conductivity effect during the pseudolinear-flow period can be handled as pseudoskin pressure drop that adds to the pressure drop caused by fluid-loss damage. The combination of the pseudolinear-flow analysis with other interpretation techniques is illustrated through examples of field cases.

Cinco-Ley, H.; Samanlego, V.F. (Univ. of Mexico/Pemex (MX)); Rodriguez, F. (Univ. of Mexico/IMP (MX))

1989-09-01T23:59:59.000Z

353

Unconventional Groundwater System Proves Effective in Reducing...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Unconventional Groundwater System Proves Effective in Reducing Contamination at West Valley Demonstration Project Unconventional Groundwater System Proves Effective in Reducing...

354

A Modeling and Optimization Approach for Multiple Energy Carrier Power Flow  

E-Print Network (OSTI)

Abstract — This paper presents a general power flow and optimization approach for power systems including multiple energy carriers, such as electricity, natural gas, and district heat. The model is based on a conceptual approach for the inclusion of distributed resources. Couplings between the different energy carriers are regarded explicitly, enabling investigations in power flow and marginal price interactions. Optimal demand, conversion, and transmission of multiple energy carriers within a system is formulated as a combined optimal power flow problem. A numerical example demonstrates how the method can be used for different system studies. I.

Martin Geidl; Göran Andersson

2005-01-01T23:59:59.000Z

355

Topographic Influences on Wind-Driven, Stratified Flow in a ?-Plane Channel: An Idealized Model for the Antarctic Circumpolar Current  

Science Conference Proceedings (OSTI)

Topographic influences are examined in an eddy-resolving model of oceanic channel flow forced by steady zonal winds. With small explicit lateral friction, transient eddies generated by the baroclinic instability of the mean flow transfer momentum ...

A. M. Treguier; J. C. McWilliams

1990-03-01T23:59:59.000Z

356

Modeling flow and transport in unsaturated fractured rock: An evaluation of the continuum approach  

Science Conference Proceedings (OSTI)

Because the continuum approach is relatively simple and straightforward to implement, it has been commonly used in modeling flow and transport in unsaturated fractured rock. However, the usefulness of this approach can be questioned in terms of its adequacy for representing fingering flow and transport in unsaturated fractured rock. The continuum approach thus needs to be evaluated carefully by comparing simulation results with field observations directly related to unsaturated flow and transport processes. This paper reports on such an evaluation, based on a combination of model calibration and prediction, using data from an infiltration test carried out in a densely fractured rock within the unsaturated zone of Yucca Mountain, Nevada. Comparisons between experimental and modeling results show that the continuum approach may be able to capture important features of flow and transport processes observed from the test. The modeling results also show that matrix diffusion may have a significant effect on the overall transport behavior in unsaturated fractured rocks, which can be used to estimate effective fracture-matrix interface areas based on tracer transport data. While more theoretical, numerical, and experimental studies are needed to provide a conclusive evaluation, this study suggests that the continuum approach is useful for modeling flow and transport in unsaturated, densely fractured rock.

Liu, Hui-Hai; Haukwa, Charles B.; Ahlers, C. Fredrik; Bodvarsson, Gudmundur S.; Flint, Alan L.; Guertal, William B.

2002-09-01T23:59:59.000Z

357

Advanced Technology for Groundwater Protection  

Science Conference Proceedings (OSTI)

This report documents the evaluation of automatic and in situ groundwater monitoring technologies for application at nuclear power plant (NPP) sites. The project studies the state of technology of automatic and in situ groundwater monitoring technologies and assesses whether they can be used to enhance the current groundwater monitoring capabilities at NPPs. Technologies for automatically detecting tritium and technologies that monitor non-radiological groundwater characteristics were explored. The abili...

2012-04-25T23:59:59.000Z

358

Radial flow has little effect on clusterization at intermediate energies in the framework of the Lattice Gas Model  

E-Print Network (OSTI)

The Lattice Gas Model was extended to incorporate the effect of radial flow. Contrary to popular belief, radial flow has little effect on the clusterization process in intermediate energy heavy-ion collisions except adding an ordered motion to the particles in the fragmentation source. We compared the results from the lattice gas model with and without radial flow to experimental data. We found that charge yields from central collisions are not significantly affected by inclusion of any reasonable radial flow.

C. B. Das; L. Shi; S. Das Gupta

2004-07-20T23:59:59.000Z

359

Nonlinear Control and Modeling of Rotating Stall in an Axial Flow Compressor  

E-Print Network (OSTI)

This thesis focuses on understanding the use of air injection as a means of controlling rotating stall in an axial flow compressor, involving modeling, dynamical systems analysis, and experimental investigations. The first step towards this understanding was the development of a low order model for air injection control, the starting point of which was the Moore and Greitzer model for axial flow compressors. The Moore and Greitzer model was extended to include the effects of air injection and bifurcation analysis was performed to determine how the closed loop system dynamics are different from those of the open loop system. This low order model was then used to determine the optimal placement of the air injection actuators. Experimental work focused on verifying that the low order model, developed for air injection actuation, qualitatively captured the behavior of the Caltech compressor rig. Open loop tests were performed to determine how the placement of the air injectors on the rig a...

Robert L. Behnken; Robert L. Behnken

1997-01-01T23:59:59.000Z

360

Proceedings of the workshop on numerical modeling of thermohydrological flow in fractured rock masses  

DOE Green Energy (OSTI)

Nineteen papers were presented at the workshop on modeling thermohydrologic flow in fractured masses. This workshop was a result of the interest currently being given to the isolation of nuclear wastes in geologic formations. Included in these proceedings are eighteen of the presentations, one abstract and summaries of the panel discussions. The papers are listed under the following categories: introduction; overviews; fracture modelings; repository studies; geothermal models; and recent developments. Eighteen of the papers have been abstracted and indexed.

Not Available

1980-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Modeling Plasma Flow in a Magnetic Nozzle with the Lattice-Boltzmann Method  

E-Print Network (OSTI)

Magnetic nozzles must convert thermal or gyro energy of the plasma to thrust while also inducing plasma detachment in order to be effective. Plasma detachment and methods to induce plasma detachment are examined. In particular, super Alfvenic detachment and resistive detachment are examined. A parametric study of the plasma flow is conducted. Plasma flow through a magnetic nozzle is simulated using a three-dimensional, timedependent magnetohydrodynamics (MHD) model. The MHD equations are modeled using the lattice-Boltzmann method and the linearized Boltzmann equation with the Bhatnagar-Gross-Krook operator for collisions. This thesis presents simulations of configurations and conditions related to the VASIMR propulsion scheme. This research demonstrates plasma detachment using resistive and super Alfvenic mechanisms by modeling plasma flow with the Lattice Boltzmann Method.

Ebersohn, Frans Hendrik

2010-05-01T23:59:59.000Z

362

Elliptic flow from pQCD + saturation + hydro model  

E-Print Network (OSTI)

We have previously predicted multiplicities and transverse momentum spectra of hadrons for the most central LHC Pb+Pb collisions at $\\sqrt{s_{NN}}=5.5$ TeV using initial state for hydrodynamic evolution from pQCD + final state saturation model. By considering binary collision and wounded nucleon profiles we extend these studies to non-central collisions, and predict the $p_{T}$ dependence of minimum bias $v_{2}$ for pions at the LHC. For protons we also show how the $p_{T}$ dependence of $v_2$ changes from RHIC to the LHC.

K. J. Eskola; H. Niemi; P. V. Ruuskanen

2007-05-15T23:59:59.000Z

363

Elliptic flow from pQCD + saturation + hydro model  

E-Print Network (OSTI)

We have previously predicted multiplicities and transverse momentum spectra of hadrons for the most central LHC Pb+Pb collisions at $\\sqrt{s_{NN}}=5.5$ TeV using initial state for hydrodynamic evolution from pQCD + final state saturation model. By considering binary collision and wounded nucleon profiles we extend these studies to non-central collisions, and predict the $p_{T}$ dependence of minimum bias $v_{2}$ for pions at the LHC. For protons we also show how the $p_{T}$ dependence of $v_2$ changes from RHIC to the LHC.

Eskola, K J; Ruuskanen, P V

2008-01-01T23:59:59.000Z

364

Heat Flow From Four New Research Drill Holes In The Western Cascades,  

Open Energy Info (EERE)

From Four New Research Drill Holes In The Western Cascades, From Four New Research Drill Holes In The Western Cascades, Oregon, Usa Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Heat Flow From Four New Research Drill Holes In The Western Cascades, Oregon, Usa Details Activities (1) Areas (1) Regions (0) Abstract: Conceptual models of the thermal structure of the Oregon Cascade Range propose either (1) a narrow zone of magmatic heat sources, flanked by shallow heat-flow anomalies caused by lateral ground-water flow; or (2) a wide zone of magmatic heat sources, with localized, generally negligible ground-water effects. The proposed narrow heat source coincides with the Quaternary volcanic arc, whereas the wider heat source would extend 10-30 km west of the arc. To test the models, four new heat-flow holes were sited

365

Measurement of Flow Phenomena in a Lower Plenum Model of a Prismatic Gas-Cooled Reactor  

Science Conference Proceedings (OSTI)

Mean-velocity-field and turbulence data are presented that measure turbulent flow phenomena in an approximately 1:7 scale model of a region of the lower plenum of a typical prismatic gas-cooled reactor (GCR) similar to a General Atomics Gas-Turbine-Modular Helium Reactor (GTMHR) design. The data were obtained in the Matched-Index-of-Refraction (MIR) facility at Idaho National Laboratory (INL) and are offered for assessing computational fluid dynamics (CFD) software. This experiment has been selected as the first Standard Problem endorsed by the Generation IV International Forum. This paper reviews the experimental apparatus and procedures, presents a sample of the data set, and reviews the INL Standard Problem. Results concentrate on the region of the lower plenum near its far reflector wall (away from the outlet duct). The flow in the lower plenum consists of multiple jets injected into a confined cross flow - with obstructions. The model consists of a row of full circular posts along its centerline with half-posts on the two parallel walls to approximate flow scaled to that expected from the staggered parallel rows of posts in the reactor design. The model is fabricated from clear, fused quartz to match the refractive-index of the mineral oil working fluid so that optical techniques may be employed for the measurements. The benefit of the MIR technique is that it permits optical measurements to determine flow characteristics in complex passages in and around objects to be obtained without locating intrusive transducers that will disturb the flow field and without distortion of the optical paths. An advantage of the INL system is its large size, leading to improved spatial and temporal resolution compared to similar facilities at smaller scales. A three-dimensional (3-D) Particle Image Velocimetry (PIV) system was used to collect the data. Inlet jet Reynolds numbers (based on the jet diameter and the time-mean average flow rate) are approximately 4,300 and 12,400. Uncertainty analysis and a discussion of the standard problem are included. The measurements reveal undeveloped, non-uniform, turbulent flow in the inlet jets and complicated flow patterns in the model lower plenum. Data include three-dimensional vector plots, data displays along the coordinate planes (slices) and presentations that describe the component flows at specific regions in the model. Information on inlet conditions are also presented.

Hugh M. McIlroy, Jr.; Donald M. McEligot; Robert J. Pink

2008-05-01T23:59:59.000Z

366

Computer modeling of gas flow and gas loading of rock in a bench blasting environment  

SciTech Connect

Numerical modeling can contribute greatly to an understanding of the physics involved in the blasting process. This paper will describe the latest enhancements to the blast modeling code DMC (Distinct Motion Code) (Taylor and Preece, 1989) and will demonstrate the ability of DMC to model gas flow and rock motion in a bench blasting environment. DMC has been used previously to model rock motion associated with blasting in a cratering environment (Preece and Taylor, 1990) and in confined volume blasting associated with in-situ oil shale retorting (Preece, 1990 a b). These applications of DMC treated the explosive loading as force versus time functions on specific spheres which were adjusted to obtain correct face velocities. It was recognized that a great need in explosives modeling was the coupling of an ability to simulate gas flow with the rock motion simulation capability of DMC. This was accomplished by executing a finite difference code that computes gas flow through a porous media (Baer and Gross, 1989) in conjunction with DMC. The marriage of these two capabilities has been documented by Preece and Knudsen, 1991. The capabilities that have been added recently to DMC and which will be documented in this paper include: (1) addition of a new equation of state for the explosive gases; (2) modeling of gas flow and sphere loading in a bench environment. 8 refs., 5 figs.

Preece, D.S.; Baer, M.R. (Sandia National Labs., Albuquerque, NM (United States)); Knudsen, S.D. (RE/SPEC, Inc., Albuquerque, NM (United States))

1991-01-01T23:59:59.000Z

367

Physical Model Development and Benchmarking for MHD Flows in Blanket Design  

SciTech Connect

An advanced simulation environment to model incompressible MHD flows relevant to blanket conditions in fusion reactors has been developed at HyPerComp in research collaboration with TEXCEL. The goals of this phase-II project are two-fold: The first is the incorporation of crucial physical phenomena such as induced magnetic field modeling, and extending the capabilities beyond fluid flow prediction to model heat transfer with natural convection and mass transfer including tritium transport and permeation. The second is the design of a sequence of benchmark tests to establish code competence for several classes of physical phenomena in isolation as well as in select (termed here as “canonical”,) combinations. No previous attempts to develop such a comprehensive MHD modeling capability exist in the literature, and this study represents essentially uncharted territory. During the course of this Phase-II project, a significant breakthrough was achieved in modeling liquid metal flows at high Hartmann numbers. We developed a unique mathematical technique to accurately compute the fluid flow in complex geometries at extremely high Hartmann numbers (10,000 and greater), thus extending the state of the art of liquid metal MHD modeling relevant to fusion reactors at the present time. These developments have been published in noted international journals. A sequence of theoretical and experimental results was used to verify and validate the results obtained. The code was applied to a complete DCLL module simulation study with promising results.

Ramakanth Munipalli; P.-Y.Huang; C.Chandler; C.Rowell; M.-J.Ni; N.Morley; S.Smolentsev; M.Abdou

2008-06-05T23:59:59.000Z

368

Variable Density Flow Modeling for Simulation Framework for Regional Geologic CO{sub 2} Storage Along Arches Province of Midwestern United States  

SciTech Connect

The Arches Province in the Midwestern U.S. has been identified as a major area for carbon dioxide (CO{sub 2}) storage applications because of the intersection of Mt. Simon sandstone reservoir thickness and permeability. To better understand large-scale CO{sub 2} storage infrastructure requirements in the Arches Province, variable density scoping level modeling was completed. Three main tasks were completed for the variable density modeling: Single-phase, variable density groundwater flow modeling; Scoping level multi-phase simulations; and Preliminary basin-scale multi-phase simulations. The variable density modeling task was successful in evaluating appropriate input data for the Arches Province numerical simulations. Data from the geocellular model developed earlier in the project were translated into preliminary numerical models. These models were calibrated to observed conditions in the Mt. Simon, suggesting a suitable geologic depiction of the system. The initial models were used to assess boundary conditions, calibrate to reservoir conditions, examine grid dimensions, evaluate upscaling items, and develop regional storage field scenarios. The task also provided practical information on items related to CO{sub 2} storage applications in the Arches Province such as pressure buildup estimates, well spacing limitations, and injection field arrangements. The Arches Simulation project is a three-year effort and part of the United States Department of Energy (U.S. DOE)/National Energy Technology Laboratory (NETL) program on innovative and advanced technologies and protocols for monitoring/verification/accounting (MVA), simulation, and risk assessment of CO{sub 2} sequestration in geologic formations. The overall objective of the project is to develop a simulation framework for regional geologic CO{sub 2} storage infrastructure along the Arches Province of the Midwestern U.S.

Joel Sminchak

2011-09-30T23:59:59.000Z

369

Models for estimating saturation flow and maximum demand at closely spaced intersections  

E-Print Network (OSTI)

This thesis describes models for saturation flow and maximum demand at closely spaced intersections. The effects of queue interaction between these two intersections are taken into account in both models. The saturation flow model is based on the Prosser-Dunne model. The presence of queues in the inter-signal link causes a reduction in saturation flow and capacity. The analytical model on which the methodology is based assumes that upstream movements discharge at their normal saturation flow rate or arrival flow rate until the downstream queue extends back to the upstream intersection and blocking occurs. The model calculates the capacities of movements at the upstream intersection as a reduced effective green period. The model can be used to estimate capacities at paired intersections with multiple upstream and downstream green periods. The results from the model are compared with TRAF-NETSIM simulation results. The results of this comparison show that the model predicts throughput better when movements at the upstream intersection (for which throughput are being calculated) are oversaturated. This thesis recommends that the capacity of movements be calculated using the reduced effective green period rather than the reduced saturation flow. The second model developed as a part of this research predicts the maximum demand at the downstream intersection. The through movement at the upstream intersection is assumed to be oversaturated and cross street movements are not considered. The analysis shows that either the upstream capacity, downstream capacity or storage capacity becomes critical and influences the maximum demand depending on the different combinations of upstream and downstream green and storage spacing considered. The demand from the models is used as input to the 1994 Highway Capacity Manual (HCM) delay equation and the delay compared with that simulated by TRAF-NETSIM for various cases. The comparison shows that the models developed predict values that compare favorably with results from TRAF NETSIM. It is recommended that the models be used to compute the upper bound for the HCM delay equation for the cases analyzed.

Nanduri, Sreelata

1995-01-01T23:59:59.000Z

370

Modeling fluid flow through single fracture using experimental, stochastic, and simulation approaches  

E-Print Network (OSTI)

This research presents an approach to accurately simulate flow experiments through a fractured core using experimental, stochastic, and simulation techniques. Very often, a fracture is assumed as a set of smooth parallel plates separated by a constant width. However, the flow characteristics of an actual fracture surface are quite different, affected by tortuosity and the impact of surface roughness. Though several researchers have discussed the effect of friction on flow reduction, their efforts lack corroboration from experimental data and have not converged to form a unified methodology for studying flow on a rough fracture surface. In this study, an integrated methodology involving experimental, stochastic, and numerical simulations that incorporate the fracture roughness and the friction factor is shown to describe flow through single fractures more efficiently. Laboratory experiments were performed to support the study in quantifying the flow contributions from the matrix and the fracture. The results were used to modify the cubic law through reservoir simulations. Observations suggest that the fracture apertures need to be distributed to accurately model the experimental results. The methodology successfully modeled fractured core experiments, which were earlier not possible using the parallel plate approach. A gravity drainage experiment using an X-ray CT scan of a fractured core has also validated the methodology.

Alfred, Dicman

2003-12-01T23:59:59.000Z

371

Analytical solution for two-phase flow in a wellbore using the drift-flux model  

SciTech Connect

This paper presents analytical solutions for steady-state, compressible two-phase flow through a wellbore under isothermal conditions using the drift flux conceptual model. Although only applicable to highly idealized systems, the analytical solutions are useful for verifying numerical simulation capabilities that can handle much more complicated systems, and can be used in their own right for gaining insight about two-phase flow processes in wells. The analytical solutions are obtained by solving the mixture momentum equation of steady-state, two-phase flow with an assumption that the two phases are immiscible. These analytical solutions describe the steady-state behavior of two-phase flow in the wellbore, including profiles of phase saturation, phase velocities, and pressure gradients, as affected by the total mass flow rate, phase mass fraction, and drift velocity (i.e., the slip between two phases). Close matching between the analytical solutions and numerical solutions for a hypothetical CO{sub 2} leakage problem as well as to field data from a CO{sub 2} production well indicates that the analytical solution is capable of capturing the major features of steady-state two-phase flow through an open wellbore, and that the related assumptions and simplifications are justified for many actual systems. In addition, we demonstrate the utility of the analytical solution to evaluate how the bottomhole pressure in a well in which CO{sub 2} is leaking upward responds to the mass flow rate of CO{sub 2}-water mixture.

Pan, L.; Webb, S.W.; Oldenburg, C.M.

2011-11-01T23:59:59.000Z

372

Physics and modeling of thermal flow and soil mechanics in unconsolidated porous media  

SciTech Connect

This paper describes a new formulation of nonlinear soil mechanics and multiphase thermal flow. The nonlinearites of the soil behavior and their interactions with fluid flow causing shear failure of the soil are the dominant features of the process. The numerical formulation of the coupled flow/stress solution model includes nonlinear compressibility and flow properties as functions of pressure, stress, and temperature; nonlinear, incremental, thermal poroelastic stress analysis; and shear or tensile failure and its effects on transport properties, porosity, and stress. An efficient sequential numerical scheme was developed. It is mass conservative and applicable to external coupling of existing simulators. The 1D examples show some startling new features of reservoir mechanics in unconsolidated media.

Settari, A. (Simtech Consulting Services Ltd. (US))

1992-02-01T23:59:59.000Z

373

Combined seismic and hydraulic method of modeling flow in fractured low permeability rocks  

DOE Green Energy (OSTI)

Modeling flow of ground water in hard rocks where a network of fractures provides the dominant flow paths is a major problem. This paper summarizes a program of investigations currently underway in this laboratory to characterize the geometry of fractured rocks and develop methods of handling flow in such systems. Numerical models have been developed to investigate flow behavior in two- and three-dimensional fracture networks. The results demonstrate the insights that can be gained from modeling studies of fractured rocks. A key problem is gathering the necessary data on fracture geometry. Investigations have been started to determine how vertical seismic profiling (VSP) might be improved and applied to this problem. A VSP experiment in The Geysers geothermal field in northern California, where fracture orientation is known, produced shear wave splitting and velocity anisotropy in agreement with theory. The results suggest the potential application of 3-component, multi-source VSP data in determining fracture orientation and average spacing. We believe a combination of seismic and hydraulic methods can greatly enhance an understanding of fluid flow and transport in low permeability rock systems where fractures provide the dominant paths. 40 refs, 16 figs., 4 tabs.

Witherspoon, P.A.; Long, J.C.S.; Majer, E.L.; Myer, L.R.

1987-06-01T23:59:59.000Z

374

Relations between Precipitation and Shallow Groundwater in Illinois  

Science Conference Proceedings (OSTI)

The statistical relationships between monthly precipitation (P) and shallow groundwater levels (GW) in 20 wells scattered across Illinois with data for 1960–84 were defined using autoregressive integrated moving average (ARIMA) modeling. A lag of ...

Stanley A. Changnon; Floyd A. Huff; Chin-Fei Hsu

1988-12-01T23:59:59.000Z

375

Geothermal groundwater heat pump. Equipment selection procedures for architects, designers and contractors  

SciTech Connect

This brochure covers the following: the way the heat pump works, why use groundwater, groundwater availability and disposal, regulations, the coefficient of performance, heat pump maintenance and reliability, heating and cooling load calculations, fuel requirement calculations, choice of equipment, calculation of water flow requirement, well pump and supply/return pipes, and design examples. (MHR)

1981-01-01T23:59:59.000Z

376

CFD modeling of commercial-scale entrained-flow coal gasifiers  

SciTech Connect

Optimization of an advanced coal-fired integrated gasification combined cycle system requires an accurate numerical prediction of gasifier performance. Computational fluid dynamics (CFD) has been used to model the turbulent multiphase reacting flow inside commercial-scale entrained-flow coal gasifiers. Due to the complexity of the physical and chemical processes involved, the accuracy of sub-models requires further improvement. Built upon a previously developed CFD model for entrained-flow gasification, the advanced physical and chemical sub-models presented in this paper include a moisture vaporization model with consideration of high mass transfer rate and a coal devolatilization model with more species to represent coal volatiles and the heating rate effect on volatile yield. The global gas phase reaction kinetics is also carefully selected. To predict a reasonable peak temperature of the coal/O{sub 2} flame inside an entrained-flow gasifier, the reserve reaction of H{sub 2} oxidation is included in the gas phase reaction model. The enhanced CFD model is applied to simulate two typical commercial-scale oxygen-blown entrained-flow configurations including a single-stage down-fired gasifier and a two-stage up-fired gasifier. The CFD results are reasonable in terms of predicted carbon conversion, syngas exit temperature, and syngas exit composition. The predicted profiles of velocity, temperature, and species mole fractions inside the entrained-flow gasifier models show trends similar to those observed in a diffusion-type flame. The predicted distributions of mole fractions of major species inside both gasifiers can be explained by the heterogeneous combustion and gasification reactions and the homogeneous gas phase reactions. It was also found that the syngas compositions at the CFD model exits are not in chemical equilibrium, indicating the kinetics for both heterogeneous and gas phase homogeneous reactions are important. Overall, the results achieved here indicate that the gasifier models reported in this paper are reliable and accurate enough to be incorporated into process/CFD co-simulations of IGCC power plants for system-wide design and optimization.

Ma, J.; Zitney, S.

2012-01-01T23:59:59.000Z

377

Groundwater Monitoring at NETL-Albany  

NLE Websites -- All DOE Office Websites (Extended Search)

About NETL About NETL Groundwater Monitoring at NETL-Albany GEO Probe Ground Water Testing Program NETL is committed to the safety and health of its employees and of nearby residents and to protecting the environment. As part of a DOE environmental protection program, NETL initiated a ground water monitoring program in 2001 with the Oregon Department of Environmental Quality (DEQ) to evaluate the groundwater flowing beneath the Albany, OR facility. Ground water monitoring wells were installed at that time, and periodic samples were taken. In March 2005, a newly-installed monitoring well on NETL's property indicated elevated ground water levels of a chemical commonly used as a degreaser or solvent until the late 1970's, trichloroethene (TCE). TCE is of concern because prolonged exposure may cause health problems, and it has been identified as a probable human carcinogen (cancer-causing substance).

378

A fully coupled finite element model of coal deformation and two phase flow for coalbed methane extraction.  

E-Print Network (OSTI)

??A reservoir simulation model is usually required to represent the combined effects of gas transport, water flow, and coal swelling/shrinking on the extraction of coalbed… (more)

Chen, Dong

2012-01-01T23:59:59.000Z

379

A Dynamic Two-Phase Flow Model of Proton Exchange Membrane Fuel Cells  

E-Print Network (OSTI)

A dynamic two phase flow model for proton exchange membrane (PEM) fuel cells is presented. The two dimensional along-the-channel model includes the two phase flow of water (gaseous and liquid) in the porous diffusion layers and in the catalyst layers, as well as the transport of the species in the gas phase. Moreover, proton and water transport in the membrane and the oxygen reduction reaction in the cathodic catalyst layer is accounted for. The discretisation of the resulting flow equations is done by a mixed finite element approach. Based on this the transport equations for the species in each phase are discretised by a finite volume scheme. The coupled mixed finite element/finite volume approach gives the spatially resolved water and gas saturation and the species concentrations. In order to describe the charge transport in the fuel cell the Poisson equations for the electrons and protons are solved by using Galerkin finite element schemes.

Karsten Kühn; K. Kühn; Mario Ohlberger; Jürgen O. Schumacher; C. Ziegler; R. Klöfkorn; Karsten Kühn Ab; Mario Ohlberger Cd; Jürgen O. Schumacher A; Christoph Ziegler; Robert Klöfkorn C

2003-01-01T23:59:59.000Z

380

A Model for Flow and Dispersion Around Buildings and Its Validation Using Laboratory Measurements  

DOE Green Energy (OSTI)

Numerical modeling of airflow and pollutant dispersion around buildings is a challenging task due to the geometrical variations of buildings and the extremely complex flow created by such surface-mounted obstacles. The airflow around buildings inevitably involves impingement and separation regions, a multiple vortex system with building wakes, and jetting effects in street canyons. The interference from adjacent buildings further complicates the flow and dispersion patterns. Thus accurate simulations of such flow and pollutant transport require not only appropriate physics submodels but also accurate numerics and significant computing resources. We have developed an efficient, high resolution CFD model for such purposes, with a primary goal to support incident response and preparedness in emergency response planning, vulnerability analysis, and the development of mitigation techniques.

Chan, S.T.; Stevens, D.; Lee, R.

2000-05-17T23:59:59.000Z

Note: This page contains sample records for the topic "groundwater flow model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Subsurface flow and transport of organic chemicals: an assessment of current modeling capability and priority directions for future research (1987-1995)  

SciTech Connect

Theoretical and computer modeling capability for assessing the subsurface movement and fate of organic contaminants in groundwater was examined. Hence, this study is particularly concerned with energy-related, organic compounds that could enter a subsurface environment and move as components of a liquid phase separate from groundwater. The migration of organic chemicals that exist in an aqueous dissolved state is certainly a part of this more general scenario. However, modeling of the transport of chemicals in aqueous solution has already been the subject of several reviews. Hence, this study emphasizes the multiphase scenario. This study was initiated to focus on the important physicochemical processes that control the behavior of organic substances in groundwater systems, to evaluate the theory describing these processes, and to search for and evaluate computer codes that implement models that correctly conceptualize the problem situation. This study is not a code inventory, and no effort was made to identify every available code capable of representing a particular process.

Streile, G.P.; Simmons, C.S.

1986-09-01T23:59:59.000Z

382

Fracture Modeling and Flow Behavior in Shale Gas Reservoirs Using Discrete Fracture Networks  

E-Print Network (OSTI)

Fluid flow process in fractured reservoirs is controlled primarily by the connectivity of fractures. The presence of fractures in these reservoirs significantly affects the mechanism of fluid flow. They have led to problems in the reservoir which results in early water breakthroughs, reduced tertiary recovery efficiency due to channeling of injected gas or fluids, dynamic calculations of recoverable hydrocarbons that are much less than static mass balance ones due to reservoir compartmentalization, and dramatic production changes due to changes in reservoir pressure as fractures close down as conduits. These often lead to reduced ultimate recoveries or higher production costs. Generally, modeling flow behavior and mass transport in fractured porous media is done using the dual-continuum concept in which fracture and matrix are modeled as two separate kinds of continua occupying the same control volume (element) in space. This type of numerical model cannot reproduce many commonly observed types of fractured reservoir behavior since they do not explicitly model the geometry of discrete fractures, solution features, and bedding that control flow pathway geometry. This inaccurate model of discrete feature connectivity results in inaccurate flow predictions in areas of the reservoir where there is not good well control. Discrete Fracture Networks (DFN) model has been developed to aid is solving some of these problems experienced by using the dual continuum models. The Discrete Fracture Networks (DFN) approach involves analysis and modeling which explicitly incorporates the geometry and properties of discrete features as a central component controlling flow and transport. DFN are stochastic models of fracture architecture that incorporate statistical scaling rules derived from analysis of fracture length, height, spacing, orientation, and aperture. This study is focused on developing a methodology for application of DFN to a shale gas reservoir and the practical application of DFN simulator (FracGen and NFflow) for fracture modeling of a shale gas reservoir and also studies the interaction of the different fracture properties on reservoir response. The most important results of the study are that a uniform fracture network distribution and fracture aperture produces the highest cumulative gas production for the different fracture networks and fracture/well properties considered.

Ogbechie, Joachim Nwabunwanne

2011-12-01T23:59:59.000Z

383

Multiphase flow modeling of oil mist and liquid film formation in oil shale retorting  

DOE Green Energy (OSTI)

A first level model is developed to account for the appearance and disappearance of liquid oil produced during oil shale retorting. Although nearly all the kerogen initially present in the oil shale exits the retort in the form of a liquid either in the form of a mist or a falling film, the flow of this valuable, clean liquid fuel is not presently accounted for in oil shale retorting computer models. A rigorous treatment of the problem is very difficult. A simplified but sophisticated treatment is developed which is designed to be easily incorporated into the LLL computer model now without major modifications to the numerical solution algorithms. A complete set of equations and simple models are developed to explicitly account for the movement of condensed oil mist and liquid film flowing at unequal velocities. The equations clearly illustrate where more detailed treatments may be inserted, as they are developed.

Lyczkowski, R.W.; Gidaspow, D.

1979-01-12T23:59:59.000Z

384

Randomized flow model and centrality measure for electrical power transmission network analysis  

E-Print Network (OSTI)

1 Randomized flow model and centrality measure for electrical power transmission network analysis. Centrality measures can then be coherently defined. An example of application to an electrical power transmission system is presented. Acknowledgements This work has been partially funded by the Foundation pour

385

A Novel Hyperbolization Procedure for The Two-Phase Six-Equation Flow Model  

SciTech Connect

We introduce a novel approach for the hyperbolization of the well-known two-phase six equation flow model. The six-equation model has been frequently used in many two-phase flow applications such as bubbly fluid flows in nuclear reactors. One major drawback of this model is that it can be arbitrarily non-hyperbolic resulting in difficulties such as numerical instability issues. Non-hyperbolic behavior can be associated with complex eigenvalues that correspond to characteristic matrix of the system. Complex eigenvalues are often due to certain flow parameter choices such as the definition of inter-facial pressure terms. In our method, we prevent the characteristic matrix receiving complex eigenvalues by fine tuning the inter-facial pressure terms with an iterative procedure. In this way, the characteristic matrix possesses all real eigenvalues meaning that the characteristic wave speeds are all real therefore the overall two-phase flowmodel becomes hyperbolic. The main advantage of this is that one can apply less diffusive highly accurate high resolution numerical schemes that often rely on explicit calculations of real eigenvalues. We note that existing non-hyperbolic models are discretized mainly based on low order highly dissipative numerical techniques in order to avoid stability issues.

Samet Y. Kadioglu; Robert Nourgaliev; Nam Dinh

2011-10-01T23:59:59.000Z

386

Model-based analysis of flow-mediated dilation and intima-media thickness  

Science Conference Proceedings (OSTI)

We present an end-to-end system for the automatic measurement of flow-mediated dilation (FMD) and intima-media thickness (IMT) for the assessment of the arterial function. The video sequences are acquired from a B-mode echographic scanner. A spline model ...

G. Bartoli; G. Menegaz; M. Lisi; G. Di Stolfo; S. Dragoni; T. Gori

2008-01-01T23:59:59.000Z

387

Wind flow modeling and simulation over the Giza Plateau cultural heritage site in Egypt  

Science Conference Proceedings (OSTI)

In this article, the wind flow over one of the most important Egyptian historical heritage sites, the Giza Plateau, was investigated using the Computational Fluid Dynamics (CFD) state-of-the-art techniques. The present study addresses the influences ... Keywords: Cultural heritage, Giza Plateau, Great Sphinx, computational fluid dynamics, wind modeling and simulation, wind over heritage sites

Ashraf S. Hussein; Hisham El-Shishiny

2009-11-01T23:59:59.000Z

388

An accurate tangential forcedisplacement model for granular-flow simulations: Contacting spheres with  

E-Print Network (OSTI)

is consistent with the elasto-plastic normal force­displacement (NFD) model presented in [ASME Journal-Quoc). URL: http://www.mae.ufl.edu/~vql. 1 Now with Parametric Technology Corp. (PTC), Needham, MA. 2 Now of the flow, play a crucial role. It has been amply demonstrated in [6] that an accurate tangential force

Vu-Quoc, Loc

389

Numerical Simulation of Flow around a Tall Isolated Seamount. Part I: Problem Formulation and Model Accuracy  

Science Conference Proceedings (OSTI)

A sigma coordinate ocean circulation model is employed to study flow trapped to a tall seamount in a periodic f-plane channel. In Part I, errors arising from the pressure gradient formulation in the steep topography/strong stratification limit ...

Aike Beckmann; Dale B. Haidvogel

1993-08-01T23:59:59.000Z

390

The NewFLOW Computational Model and Intermediate Format - Version 1.04  

E-Print Network (OSTI)

This report motivates and defines a general-purpose, architecture independent, parallel computational model, which captures the intuitions which underlie the design of the United Functions and Objects (UFO) programming language. The model has two aspects, which turn out to be a traditional dataflow model and an actor-like model, with a very simple interface between the two. Certain aspects of the model, particularly strictness, maximum parallelism, and lack of suspension are stressed. The implications of introducing stateful objects are carefully spelled out. The model has several purposes, although we primarily describe it as a vehicle for the compilation and optimisation of UFO, and for visualising the execution of programs. Having motivated the model, this report specifies, in detail, both the syntax and semantics of the model, and provides some examples of its use. 1 Motivation The primary purpose of this report is to define the semantics and syntax of NewFLOW, an intermediate rep...

Julian Seward; John Sargeant; Chris Kirkham

1996-01-01T23:59:59.000Z

391

Development of Mechanistic Modeling Capabilities for Local Neutronically-Coupled Flow-Induced Instabilities in Advanced Water-Cooled Reactors  

SciTech Connect

The major research objectives of this project included the formulation of flow and heat transfer modeling framework for the analysis of flow-induced instabilities in advanced light water nuclear reactors such as boiling water reactors. General multifield model of two-phase flow, including the necessary closure laws. Development of neurton kinetics models compatible with the proposed models of heated channel dynamics. Formulation and encoding of complete coupled neutronics/thermal-hydraulics models for the analysis of spatially-dependent local core instabilities. Computer simulations aimed at testing and validating the new models of reactor dynamics.

Michael Podowski

2009-11-30T23:59:59.000Z

392

Buda-Lund hydro model and the elliptic flow at RHIC  

E-Print Network (OSTI)

The ellipsoidally symmetric Buda-Lund hydrodynamic model describes naturally the transverse momentum and the pseudorapidity dependence of the elliptic flow in Au+Au collisions at $\\sqrt{s_{NN}} = 130$ and 200 GeV. The result confirms the indication of quark deconfinement in Au+Au collisions at RHIC, obtained from Buda-Lund hydro model fits to combined spectra and HBT radii of BRAHMS, PHOBOS, PHENIX and STAR.

M. Csanad; T. Csorgo; B. Lorstad

2004-02-12T23:59:59.000Z

393

Symmetries and Conservation Laws for the 2D Ricci Flow Model  

E-Print Network (OSTI)

The paper aims to study the connection between symmetries and conservation laws for the 2D Ricci flow model. The procedure starts by obtaining a set of multipliers which generates conservation laws. Then, using a general relation which connects symmetries and conservation laws for whatever dynamical system, one determines symmetries related to a chosen multiplier. On this basis, new similarity solutions of the model, not yet discussed in literature, are highlighted.

Rodica Cimpoiasu

2011-08-27T23:59:59.000Z

394

Symmetries and Conservation Laws for the 2D Ricci Flow Model  

E-Print Network (OSTI)

The paper aims to study the connection between symmetries and conservation laws for the 2D Ricci flow model. The procedure starts by obtaining a set of multipliers which generates conservation laws. Then, using a general relation which connects symmetries and conservation laws for whatever dynamical system, one determines symmetries related to a chosen multiplier. On this basis, new similarity solutions of the model, not yet discussed in literature, are highlighted.

Cimpoiasu, Rodica

2011-01-01T23:59:59.000Z

395

Acoustically Induced Streaming Flows near a Model Cod Otolith and their Potential Implications for Fish Hearing  

SciTech Connect

The ears of fishes are remarkable sensors for the small acoustic disturbances associated with underwater sound. For example, each ear of the Atlantic cod (Gadus morhua) has three dense bony bodies (otoliths) surrounded by fluid and tissue, and detects sounds at frequencies from 30 to 500 Hz. Atlantic cod have also been shown to localize sounds. However, how their ears perform these functions is not fully understood. Steady streaming, or time-independent, flows near a 350% scale model Atlantic cod otolith immersed in a viscous fluid were studied to determine if these fluid flows contain acoustically relevant information that could be detected by the ear s sensory hair cells. The otolith was oscillated sinusoidally at various orientations at frequencies of 8 24 Hz, corresponding to an actual frequency range of 280 830 Hz. Phaselocked particle pathline visualizations of the resulting flows give velocity, vorticity, and rate of strain fields over a single plane of this mainly two-dimensional flow. Although the streaming flows contain acoustically relevant information, the displacements due to these flows are likely too small to explain Atlantic cod hearing abilities near threshold. The results, however, may suggest a possible mechanism for detection of ultrasound in some fish species.

Kotas, Charlotte W [ORNL; Rogers, Peter [Georgia Institute of Technology; Yoda, Minami [Georgia Institute of Technology

2011-01-01T23:59:59.000Z

396

Measurement of Flow Phenomena in a Lower Plenum Model of a Prismatic Gas-Cooled Reactor  

Science Conference Proceedings (OSTI)

Mean-velocity-field and turbulence data are presented that measure turbulent flow phenomena in an approximately 1:7 scale model of a region of the lower plenum of a typical prismatic gas-cooled reactor (GCR) similar to a General Atomics Gas-Turbine-Modular Helium Reactor (GTMHR) design. The data were obtained in the Matched-Index-of-Refraction (MIR) facility at Idaho National Laboratory (INL) and are offered for assessing computational fluid dynamics (CFD) software. This experiment has been selected as the first Standard Problem endorsed by the Generation IV International Forum. Results concentrate on the region of the lower plenum near its far reflector wall (away from the outlet duct). The flow in the lower plenum consists of multiple jets injected into a confined cross flow - with obstructions. The model consists of a row of full circular posts along its centerline with half-posts on the two parallel walls to approximate geometry scaled to that expected from the staggered parallel rows of posts in the reactor design. The model is fabricated from clear, fused quartz to match the refractive-index of the working fluid so that optical techniques may be employed for the measurements. The benefit of the MIR technique is that it permits optical measurements to determine flow characteristics in complex passages in and around objects to be obtained without locating intrusive transducers that will disturb the flow field and without distortion of the optical paths. An advantage of the INL system is its large size, leading to improved spatial and temporal resolution compared to similar facilities at smaller scales. A three-dimensional (3-D) Particle Image Velocimetry (PIV) system was used to collect the data. Inlet jet Reynolds numbers (based on the jet diameter and the time-mean bulk velocity) are approximately 4,300 and 12,400. Uncertainty analyses and a discussion of the standard problem are included. The measurements reveal developing, non-uniform, turbulent flow in the inlet jets and complicated flow patterns in the model lower plenum. Data include three-dimensional vector plots, data displays along the coordinate planes (slices) and presentations that describe the component flows at specific regions in the model. Information on inlet conditions is also presented.

Hugh M. McIlroy, Jr.; Doanld M. McEligot; Robert J. Pink

2010-02-01T23:59:59.000Z

397

Analysis Of Residence Time Distribution Of Fluid Flow By Axial Dispersion Model  

Science Conference Proceedings (OSTI)

Radioactive tracer {sup 82}Br in the form of KBr-82 with activity {+-} 1 mCi has been injected into steel pipeline to qualify the extent dispersion of water flowing inside it. Internal diameter of the pipe is 3 in. The water source was originated from water tank through which the water flow gravitically into the pipeline. Two collimated sodium iodide detectors were used in this experiment each of which was placed on the top of the pipeline at the distance of 8 and 11 m from injection point respectively. Residence time distribution (RTD) curves obtained from injection of tracer are elaborated numerically to find information of the fluid flow properties. The transit time of tracer calculated from the mean residence time (MRT) of each RTD curves is 14.9 s, therefore the flow velocity of the water is 0.2 m/s. The dispersion number, D/uL, for each RTD curve estimated by using axial dispersion model are 0.055 and 0.06 respectively. These calculations are performed after fitting the simulated axial dispersion model on the experiment curves. These results indicated that the extent of dispersion of water flowing in the pipeline is in the category of intermediate.

Sugiharto [Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132 (Indonesia); Centre for Applications of Isotopes and Radiation Technology-National Nuclear Energy Agency, Jl. Lebak Bulus Raya No. 49, Jakarta 12440 (Indonesia); Su'ud, Zaki; Kurniadi, Rizal; Waris, Abdul [Centre for Applications of Isotopes and Radiation Technology-National Nuclear Energy Agency, Jl. Lebak Bulus Raya No. 49, Jakarta 12440 (Indonesia); Abidin, Zainal [Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2010-12-23T23:59:59.000Z

398

Modeling of material and energy flow in an EBCHR casting system  

Science Conference Proceedings (OSTI)

A numerical and experimental analysis is made of fluid flow and heat transfer in a continuous casting system with an electron-beam energy source. For a cylindrical ingot confined in a water-cooled crucible, a two-dimensional, steady-state model is developed which includes the effects of free convection in the pool and conduction in the two-phase and solid regions. A modified Galerkin finite element method is used to solve for the flow and temperature fields simultaneously with the upper and lower boundaries of the pool. The calculation grid deforms along vertical spines as these phase boundaries move. Heat flows are measured in a steady-state experiment involving a short ingot and no pouring. Heat transfer coefficients representing contact resistance are determined, and measured heat flows are compared with model values. Flow and temperature fields along with solidification-zone boundaries are calculated for the experimental case and a case in which the ingot cooling is improved.

Westerberg, K.W. [Aspen Technology, Inc., Cambridge, MA (United States); McClelland, M.A. [Lawrence Livermore National Lab., CA (United States)

1994-11-01T23:59:59.000Z

399

Environmental Groundwater Monitoring Report  

Office of Legacy Management (LM)

-460 -460 Environmental Groundwater Monitoring Report Third Quarter, 1997 October 1997 Approved for public release; further dissemination unlimited. Environmental Restoration U.S. Department of Energy Nevada Operations Office This report has been reproduced directly from the best available copy. 1 - I : ~vailablk to DOE and DOE contractors from the. Office of Scientific - and Technical .Information, P.O. Box 62, Oak Ridge, TN 3783 1 ; prices available from (423) 576-840 1. Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22 16 1, telephone (703) 487-4650. RULISON SITE GROUNDWATER MONITORING REPORT THIRD QUARTER, 1997 DOE Nevada Operations Office Las Vegas, Nevada

400

Two-phase flow in a vertical pipe and the phenomenon of choking: Homogeneous diffusion model. Part I. Homogeneous flow models  

DOE Green Energy (OSTI)

The paper examines the topologic structure of all possible solutions which can exist in flows through adiabatic constant-area ducts for which the homogeneous diffusion model has been assumed. The conservation equations are one-dimensional with the single space variable z, but gravity effects are included. The conservation equations are coupled with three equations of state: a pure substance, a perfect gas with constant specific heats, and a homogeneous two-phase system in thermodynamic equilibrium. The preferred state variables are pressure P, enthalpy h, and mass flux G{sup 2}. The three conservation equations are first-order but nonlinear. They induce a family of solutions which are interpreted as curves in a four-dimensional phase space conceived as a union of three-dimensional spaces (h, G{sup 2};z) with G{sup 2} = const treated as a parameter. It is shown that all points in these spaces are regular, so that no singular solutions need to be considered. The existence and uniqueness theorem leads to the conclusion that through every point in phase space there passes one and only one solution-curve. The set of differential equations, treated as a system of algebraic equations at each point of the phase space, determines the components of a rate-of-change vector which are obtained explicitly by Cramer's rule. This vector is tangent to the solution curve. Each solution curve turns downward in z at some specific elevation z*, and this determines the condition for choking. Choking occurs always when the exit flow velocity at L=z* is equal to the local velocity of propagation of small plane disturbances of sufficiently large wavelength, that is when the flow rate G becomes equal to a specified, critical flow rate, G*. A criterion, analogous to the Mach number, which indicates the presence or absence of choking in a cross-section is the ratio K=G/G** of the mass-flow rate G to the local critical mass flow rate, G**, K=1 denoting choking. The critical parameters depend only on the thermodynamic properties of the fluid and are independent of the gravitational acceleration and shearing stress at the wall. The topological characteristics of the solutions allow us to study all flow patterns which can, and which cannot, occur in a pipe of given length L into which fluid is discharged through a rounded entrance from a stagnation reservoir and whose back-pressure is slowly lowered. The set of flow patterns is analogous to that which occurs with a perfect gas, except that the characteristic numerical values are different. They must be obtained by numerical integration and the influence of gravity must be allowed for. The preceding conclusions are valid for all assumptions concerning the shearing stress at the wall which make it dependent on the state parameters only, but not on their derivatives with respect to z. However, the study is limited to upward flows for which the shearing stress at the wall and the gravitational acceleration are codirectional.

Bilicki, Z.; Kestin, J.

1982-01-01T23:59:59.000Z

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401

A phenomenological model for rarefied gas flows in thin film slider bearings  

E-Print Network (OSTI)

We analyze rarefied gas flows in lubricating films that form between the read/write head and rotating recording medium in computer hard drives. A modified slip-corrected Reynolds lubrication equation is derived for arbitrary Knudsen numbers using the Navier-Stokes equation with consistent slip boundary conditions and modified physical coefficients. In particular, we present results of velocity profiles, pressure distribution and load capacity for various slider bearing configurations. An empirical model for the velocity distribution is developed by studying the Poiseuille and Couette flow components of the lubricating film. Important lubrication characteristics such as the pressure distribution and load capacity are obtained directly from numerical solutions of the modified Reynolds equation. In addition, we outline a method to accurately predict the shear drag forces induced by air resistance to the track-access-motion of the sliders. The new model is validated by comparisons with numerical solutions of the generalized lubrication equation based on the two-dimensional linearized Boltzmann equation and Direct Simulation Monte Carlo (DSMC) results available in the literature. The model predicts the velocity profiles, pressure distribution, load capacity and skin friction with good accuracy for a wide range of Knudsen numbers for low subsonic compressible flows. However it exhibits some physical limitations in the free molecular flow regime, due to its use of a Poiseuille flowrate database obtained via the solution of a two- dimensional Boltzmann equation.

Bahukudumbi, Pradipkumar

2002-01-01T23:59:59.000Z

402

Groundwater Makes a Splash NNSS Groundwater Experts Meet at Devils...  

NLE Websites -- All DOE Office Websites (Extended Search)

specialists have been examining the effects of contamination from historic underground nuclear testing on groundwater in and around the NNSS. These experts were on hand at the...

403

An integrated media, integrated processes watershed model Gour-Tsyh Yeh a,  

E-Print Network (OSTI)

An integrated media, integrated processes watershed model Gour-Tsyh Yeh a, , Don-Sin Shih b , Jing modelling Groundwater and surface water coupling High performance parallel computing River hydraulics of a numerical model simulating fluid flow in WAterSHed Systems of 1D Stream-River Networks, 2D Overland Regime

Central Florida, University of

404

Explanation of Significant Differences Between Models used to Assess Groundwater Impacts for the Disposal of Greater-Than-Class C Low-Level Radioactive Waste and Greater-Than-Class C-Like Waste Environmental Impact Statement (DOE/EIS-0375-D) and the  

SciTech Connect

Models have been used to assess the groundwater impacts to support the Draft Environmental Impact Statement for the Disposal of Greater-Than-Class C (GTCC) Low-Level Radioactive Waste and GTCC-Like Waste (DOE-EIS 2011) for a facility sited at the Idaho National Laboratory and the Environmental Assessment for the INL Remote-Handled Low-Level Waste Disposal Project (INL 2011). Groundwater impacts are primarily a function of (1) location determining the geologic and hydrologic setting, (2) disposal facility configuration, and (3) radionuclide source, including waste form and release from the waste form. In reviewing the assumptions made between the model parameters for the two different groundwater impacts assessments, significant differences were identified. This report presents the two sets of model assumptions and discusses their origins and implications for resulting dose predictions. Given more similar model parameters, predicted doses would be commensurate.

Annette Schafer; Arthur S. Rood; A. Jeffrey Sondrup

2011-08-01T23:59:59.000Z

405

Experimental Modeling of VHTR Plenum Flows during Normal Operation and Pressurized Conduction Cooldown  

DOE Green Energy (OSTI)

The Very High Temperature Reactor (VHTR) is the leading candidate for the Next Generation Nuclear Power (NGNP) Project in the U.S. which has the goal of demonstrating the production of emissions free electricity and hydrogen by 2015. The present document addresses experimental modeling of flow and thermal mixing phenomena of importance during normal or reduced power operation and during a loss of forced reactor cooling (pressurized conduction cooldown) scenario. The objectives of the experiments are, 1), provide benchmark data for assessment and improvement of codes proposed for NGNP designs and safety studies, and, 2), obtain a better understanding of related phenomena, behavior and needs. Physical models of VHTR vessel upper and lower plenums which use various working fluids to scale phenomena of interest are described. The models may be used to both simulate natural convection conditions during pressurized conduction cooldown and turbulent lower plenum flow during normal or reduced power operation.

Glenn E McCreery; Keith G Condie

2006-09-01T23:59:59.000Z

406

Three-dimensional modeling of diesel engine intake flow, combustion and emissions-II  

DOE Green Energy (OSTI)

A three-dimensional computer code, KIVA, is being modified to include state-of-the-art submodels for diesel engine flow and combustion. Improved and/or new submodels which have already been implemented and previously reported are: Wall heat transfer with unsteadiness and compressibility, laminar-turbulent characteristic time combustion with unburned HC and Zeldo`vich NO{sub x}, and spray/wall impingement with rebounding and sliding drops. Progress on the implementation of improved spray drop drag and drop breakup models, the formulation and testing of a multistep kinetics ignition model and preliminary soot modeling results are described in this report. In addition, the use of a block structured version of KIVA to model the intake flow process is described. A grid generation scheme has been developed for modeling realistic (complex) engine geometries, and computations have been made of intake flow in the ports and combustion chamber of a two-intake-valve engine. The research also involves the use of the code to assess the effects of subprocesses on diesel engine performance. The accuracy of the predictions is being tested by comparisons with engine experiments. To date, comparisons have been made with measured engine cylinder pressure, temperature and heat flux data, and the model results are in good agreement with the experiments. Work is in progress that will allow validation of in-cylinder flow and soot formation predictions. An engine test facility is described that is being used to provide the needed validation data. Test results have been obtained showing the effect of injection rate and split injections on engine performance and emissions.

Reitz, R.D.; Rutland, C.J.

1993-09-01T23:59:59.000Z

407

Development of an entrained flow gasifier model for process optimization study  

SciTech Connect

Coal gasification is a versatile process to convert a solid fuel in syngas, which can be further converted and separated in hydrogen, which is a valuable and environmentally acceptable energy carrier. Different technologies (fixed beds, fluidized beds, entrained flow reactors) are used, operating under different conditions of temperature, pressure, and residence time. Process studies should be performed for defining the best plant configurations and operating conditions. Although 'gasification models' can be found in the literature simulating equilibrium reactors, a more detailed approach is required for process analysis and optimization procedures. In this work, a gasifier model is developed by using AspenPlus as a tool to be implemented in a comprehensive process model for the production of hydrogen via coal gasification. It is developed as a multizonal model by interconnecting each step of gasification (preheating, devolatilization, combustion, gasification, quench) according to the reactor configuration, that is in entrained flow reactor. The model removes the hypothesis of equilibrium by introducing the kinetics of all steps and solves the heat balance by relating the gasification temperature to the operating conditions. The model allows to predict the syngas composition as well as quantity the heat recovery (for calculating the plant efficiency), 'byproducts', and residual char. Finally, in view of future works, the development of a 'gasifier model' instead of a 'gasification model' will allow different reactor configurations to be compared.

Biagini, E.; Bardi, A.; Pannocchia, G.; Tognotti, L. [Consorzio Pisa Ric, Pisa (Italy). Div Energia Ambiente

2009-10-