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

Description: 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.
Date: April 7, 2011
Creator: AA, SPILIOTOPOULOS; LC, SWANSON; R, SHANNON & MJ, TONKIN
Partner: UNT Libraries Government Documents Department

Modeling Transport in Gas Chromatography Columns for the Micro-ChemLab

Description: The gas chromatography (GC) column is a critical component in the microsystem for chemical detection ({mu}ChemLab{trademark}) being developed at Sandia. The goal is to etch a meter-long GC column onto a 1-cm{sup 2} silicon chip while maintaining good chromatographic performance. Our design strategy is to use a modeling and simulation approach. We have developed an analytical tool that models the transport and surface interaction process to achieve an optimized design of the GC column. This analytical tool has a flow module and a separation module. The flow module considers both the compressibility and slip flow effects that may significantly influence the gas transport in a long and narrow column. The separation module models analyte transport and physico-chemical interaction with the coated surface in the GC column. It predicts the column efficiency and performance. Results of our analysis will be presented in this paper. In addition to the analytical tool, we have also developed a time-dependent adsorption/desorption model and incorporated this model into a computational fluid dynamics (CFD) code to simulate analyte transport and separation process in GC columns. CFD simulations can capture the complex three-dimensional flow and transport dynamics, whereas the analytical tool cannot. Different column geometries have been studied, and results will be presented in this paper. Overall we have demonstrated that the modeling and simulation approach can guide the design of the GC column and will reduce the number of iterations in the device development.
Date: September 1, 1999
Creator: ADKINS,DOUGLAS R.; FRYE-MASON,GREGORY CHARLES; HUDSON,MARY L.; KOTTENSTETTE,RICHARD; MATZKE,CAROLYN M.; SALINGER,ANDREW G. et al.
Partner: UNT Libraries Government Documents Department

Analysis of Tracer Tests with Multirate Diffusion Models: Recent Results and Future Directions within the WIPP Project

Description: A series of single-well injection-withdrawal (SWIW) and two-well convergent-flow (TWCF) tracer tests were conducted in the Culebra dolomite at the WIPP site in late 1995 and early 1996. Modeling analyses over the past year have focused on reproducing the observed mass-recovery curves and understanding the basic physical processes controlling tracer transport in SWIW and TWCF tests. To date, specific modeling efforts have focused on five SWIW tests and one TWCF pathway at each of two different locations (H-11 and H-19 hydropads). An inverse parameter-estimation procedure was implemented to model the SWIW and TWCF tests with both traditional and multirate double-porosity formulations. The traditional model assumes a single diffusion rate while the multirate model uses a first-order approximation to model a continuous distribution of diffusion coefficients. Conceptually, the multirate model represents variable matrix block sizes within the Culebra as observed in geologic investigations and also variability in diffusion rates within the matrix blocks as observed with X-ray imaging in the laboratory. Single-rate double-porosity models cannot provide an adequate match to the SWIW data. Multirate double-porosity models provide excellent fits to all five SWIW mass-recovery curves. Models of the TWCF tests show that, at one location, the tracer test can be modeled with both single-rate and multirate double-porosity models. At the other location, only the multi-rate double-porosity model is capable of explaining the test results.
Date: October 1, 1999
Creator: ALTMAN, SUSAN J.; HAGGERTY, ROY; MCKENNA, SEAN A. & MEIGS, LUCY C.
Partner: UNT Libraries Government Documents Department

Approaches to large scale unsaturated flow in heterogeneous, stratified, and fractured geologic media

Description: This report develops a broad review and assessment of quantitative modeling approaches and data requirements for large-scale subsurface flow in radioactive waste geologic repository. The data review includes discussions of controlled field experiments, existing contamination sites, and site-specific hydrogeologic conditions at Yucca Mountain. Local-scale constitutive models for the unsaturated hydrodynamic properties of geologic media are analyzed, with particular emphasis on the effect of structural characteristics of the medium. The report further reviews and analyzes large-scale hydrogeologic spatial variability from aquifer data, unsaturated soil data, and fracture network data gathered from the literature. Finally, various modeling strategies toward large-scale flow simulations are assessed, including direct high-resolution simulation, and coarse-scale simulation based on auxiliary hydrodynamic models such as single equivalent continuum and dual-porosity continuum. The roles of anisotropy, fracturing, and broad-band spatial variability are emphasized. 252 refs.
Date: August 1, 1991
Creator: Ababou, R.
Partner: UNT Libraries Government Documents Department

A nonlinear dynamic model of a once-through, helical-coil steam generator

Description: A dynamic model of a once-through, helical-coil steam generator is presented. The model simulates the advanced liquid metal reactor superheated cycle steam generator with a four-region, moving-boundary, drift-flux model. The model is described by a set of nonlinear differential equations derived from the fundamental equations of conversation of mass, energy, and momentum. Sample results of steady-state and transient calculations are presented.
Date: July 1, 1993
Creator: Abdalla, M. A.
Partner: UNT Libraries Government Documents Department

Geochemistry of Salado Formation brines recovered from the Waste Isolation Pilot Plant (WIPP) repository

Description: Intergranular brines recovered from the repository horizon of the Waste Isolation Pilot Plant (WIPP) have major- and trace-element compositions that reflect seawater evaporation and diagenetic processes. Brines obtained from repository drill holes are heterogenous with respect to composition, but their compositional fields are distinct from those obtained from fluid inclusions in WIPP halite. The heterogeneity of brine compositions within the drill-hole population indicates a lack of mixing and fluid homogenization within the salt at the repository level. Compositional differences between intergranular (drill hole) and intragranular (fluid inclusions) brines is attributed to isolation of the latter from diagenetic fluids that were produced from dehydration reactions involving gypsum and clay minerals. Modeling of brine-rock equilibria indicates that equilibration with evaporite minerals controls the concentrations of major elements in the brine. Drill-hole brines are in equilibrium with the observed repository minerals halite, anhydrite, magnesite, polyhalite and quartz. The equilibrium model supports the derivation of drill-hole brines from near-field fluid, rather than large-scale vertical migration of fluids from the overlying Rustler or underlying Castile Formations. 13 refs., 6 figs., 6 tabs.
Date: January 1, 1990
Creator: Abitz, R.; Myers, J.; Drez, P. & Deal, D.
Partner: UNT Libraries Government Documents Department

Thermal and flow considerations for the 80 K shield of the SSC magnet cryostats

Description: The nominal temperatures in the SSC cryostat range between 4.2 K in the superconducting magnet and 300 K on the cryostat outer wall. To minimize the 4 K heat load, a thermal shield cooled by liquid and vapor nitrogen flows at 84 K and one a 20 K cooled by helium flow are incorporated in the cryostat. Tubes attached to the shields serve as conduits for cryogens. The liquid nitrogen tube in the cryostat is used for cryostat refrigeration and also for liquid distribution around the SSC rings. The second nitrogen line is used to return the vapor to the helium refrigerators for further processing. The nominal GN2 flow from a 4.3-km long cryogenic string (4 sections) to the surface is 64 g/s. The total liquid nitrogen consumption of approximately 5000 g/s will be supplied at one, two or more locations on the surface. The total heat load of the 80 K shield is estimated as 3.2 W/m. About 50% is composed of infrared radiation and remaining 50% by heat conduction through supports, vacuum barriers and other thermal connections between the shield and the 300 K outer wall. The required LN2 flow rate depends on the distribution and circulation schemes. The LN2 temperature will in turn vary depending on the flow rate and on the recooling methods used. For example, with a massflow of 400 g/s of LN2 the temperature rises from 82 K to 86 K between two compact recoolers 1 km apart. This temperature is higher thin desired. The temperature can be reduced by increasing the flow rate of the liquid or by using the continuous recooling. This paper discusses some thermal problems caused by certain mechanical designs of the 80 K shielding the possible improvement by using continuous recooling. In the following, we present results of the ...
Date: April 1993
Creator: Abramovich, S.; Yuecel, A.; Demko, J. & Thirumaleshwar, M.
Partner: UNT Libraries Government Documents Department

Large-scale structure evolution in axisymmetric, compressible free-shear layers

Description: This paper is a description of work-in-progress. It describes Sandia`s program to study the basic fluid mechanics of large-scale mixing in unbounded, compressible, turbulent flows, specifically, the turbulent mixing of an axisymmetric compressible helium jet in a parallel, coflowing compressible air freestream. Both jet and freestream velocities are variable over a broad range, providing a wide range mixing layer Reynolds number. Although the convective Mach number, M{sub c}, range is currently limited by the present nozzle design to values of 0.6 and below, straightforward nozzle design changes would permit a wide range of convective Mach number, to well in excess of 1.0. The use of helium allows simulation of a hot jet due to the large density difference, and also aids in obtaining optical flow visualization via schlieren due to the large density gradient in the mixing layer. The work comprises a blend of analysis, experiment, and direct numerical simulation (DNS). There the authors discuss only the analytical and experimental efforts to observe and describe the evolution of the large-scale structures. The DNS work, used to compute local two-point velocity correlation data, will be discussed elsewhere.
Date: May 1, 1997
Creator: Aeschliman, D.P. & Baty, R.S.
Partner: UNT Libraries Government Documents Department

Coherent structures in compressible free-shear-layer flows

Description: Large scale coherent structures are intrinsic fluid mechanical characteristics of all free-shear flows, from incompressible to compressible, and laminar to fully turbulent. These quasi-periodic fluid structures, eddies of size comparable to the thickness of the shear layer, dominate the mixing process at the free-shear interface. As a result, large scale coherent structures greatly influence the operation and efficiency of many important commercial and defense technologies. Large scale coherent structures have been studied here in a research program that combines a synergistic blend of experiment, direct numerical simulation, and analysis. This report summarizes the work completed for this Sandia Laboratory-Directed Research and Development (LDRD) project.
Date: August 1, 1997
Creator: Aeschliman, D.P.; Baty, R.S.; Kennedy, C.A. & Chen, J.H.
Partner: UNT Libraries Government Documents Department

Development and application of performance and cost models for the externally-fired combined cycle. Task 1, Volume 2. Topical report, June 1995

Description: Increasing restrictions on emission of pollutants from conventional pulverized coal fired steam (PCFS) plant generating electrical power is raising capital and operating cost of these plants and at the same time lowering plant efficiency. This is creating a need for alternative technologies which result in lower emissions of regulated pollutants and which are thermally more efficient. Natural gas-fired combined cycle power generation systems have lower capital cost and higher efficiencies than conventional coal fired steam plants, and at this time they are the leading contender for new power plant construction in the U.S. But the intermediate and long term cost of these fuels is high and there is uncertainty regarding their long-term price and availability. Coal is a relatively low cost fuel which will be abundantly available in the long term. This has motivated the development of advanced technologies for power production from coal which will have advantages of other fuels. The Externally Fired Combined Cycle (EFCC) is one such technology. Air pollution control/hot gas cleanup issues associated with this technology are described.
Date: July 1, 1995
Creator: Agarwal, P.; Frey, H. & Rubin, E.S.
Partner: UNT Libraries Government Documents Department

Convective heat transfer in MHD channels and its influence on channel performance

Description: The limitations of the integral boundary layer methods and the potential of the differential boundary layer method in analyzing MHD channel flows are assessed. The sensitivity of results from the integral method to the parametrization of boundary layer profiles and calculation of wall heat transfer is established. A mixing-length type turbulence model for flow on rough walls is developed and validated by comparison with experimental data. The turbulence model is used in a quasi-three-dimensional boundary layer model to evaluate the influence of wall roughness and pressure gradients on the flow characteristics and performance of MHD channels. The behaviors of skin friction and Stanton number calculated from the analytical model are found to differ considerably from the empirical correlations valid for non-MHD flows without pressure gradients.
Date: January 1, 1980
Creator: Ahluwalia, R.K. & Doss, E.D.
Partner: UNT Libraries Government Documents Department

Ash and pulverized coal deposition in combustors and gasifiers. Quarterly technical progress report, July 1--September 30, 1995

Description: During this quarter, further progress has been made in accomplishing the objectives of the project. The computational model for simulating particle motions in turbulent flows has been further developed. The model was applied to the analysis of particle transport and deposition processes in a circular duct and in a plane recirculating region. A model for evaluating particle deposition rate in the presence of gravitational and electrical forces in turbulent flows formulated. Results concerning the deposition velocity of particles under various conditions were obtained. It is shown that the model predictions are in good agreement with the available experimental and digital simulation data. Experimental study of glass fiber transport and deposition rate is also being planned.
Date: December 31, 1995
Creator: Ahmadi, G.
Partner: UNT Libraries Government Documents Department

A computational model for coal transport and combustion. Final technical report

Description: In this project, a comprehensive theoretical, computational and experimental study directed toward providing a fundamental understanding of particulate flows as applied to coal transport is performed. Thermodynamically admissible constitutive expressions for the phasic stress tensors, heat and fluctuation energy flux vectors for turbulent multiphase flows were derived. The material parameters of the model were evaluated from the limiting conditions of rapid flows of dry spherical granular particles, and single-phase turbulent fluid flows. The case of simple shear flows of glass beads-water mixtures was studied. The model was extended to cover chemically active gas-solid flows. A thermodynamically consistent model for rapid flows of granular materials in a rotating frame of reference, along with a transport equation for the granular kinetic stress tensor was developed. The model parameters for the special case of spherical nearly elastic particles were evaluated. The results for the granular stresses and the normal stress differences were compared with the available simulation data and good agreement was observed. Effects of frictional loss of energy on rapid granular shear flows were studied. The previously developed kinetic based model was used and the mean velocity, the fluctuation kinetic energy and the solid volume fraction profiles were evaluated under a variety of conditions and different friction coefficients. A computational model for analyzing rapid granular in complex geometries was developed. The discrete element scheme was used and the granular flow down a chute was analyzed. The results were compared with the available experimental data, the model predictions, and the existing simulation results, and good agreements were observed. The model was used to analyze granular flows in a duct with an obstructing block. The effect of boundary condition was also included and the granular gravity flow was analyzed in details.
Date: March 1, 1995
Creator: Ahmadi, G.
Partner: UNT Libraries Government Documents Department

A computational model for coal transport and combustion. Quarterly technical progress report, June 1, 1993--August 31, 1993

Description: The objective of this project is to develop an accurate model describing turbulent flows of coal slurries, rapid flows of granular coal-air mixtures, and turbulent coal combustion processes. The other main objective is to develop a computer code incorporating the new model. Experimental verification of the foundation of the model is also included in the study. In this report the thermodynamically consistent, rate dependent model for turbulent two-phase flows analysis was used and the phasic fluctuation energy dissipation rates are evaluated. Further progress on the application of the kinetic model for rapid flows of granular materials including the frictional energy losses were made. The velocity, the fluctuation energy and the solid volume fraction profiles for granular flows down a vertical channel were obtained. The results were compared with the molecular dynamic simulations of Savage and good agreement was obtained. The computational model was used and the rapid granular flows around a rectangular block in a channel were analyzed. The effect of bumpy wall on flow of granular materials was analyzed. The special case of Couette flow was studied. The preliminary results obtained is quite encouraging. Further progress was made in the experimental study of mono-layer simple shear flow device. Preliminary data concerning the shearing of 12 mm multi-color glass particles are obtained.
Date: December 31, 1993
Creator: Ahmadi, G.
Partner: UNT Libraries Government Documents Department

A Computational Model for Coal Transport and Combustion. Quarterly Technical Progress Report, September 1, 1993--November 30, 1993

Description: In the period of September 1, 1993 to November 30, 1993, further progress was made of the theoretical and computational modeling of turbulent two-phase flows, as well as granular flows. The effect of bumpy wall on flow of granular materials was also analyzed. The special case of Couette flow was studied. Further progress was made in the experimental study of mono-layer simple shear flow device. Preliminary data concerning the sharing of 12 mm multi-color glass particles are obtained. The preliminary experimental data show the expected variation. A detailed progress report for project review was also prepared which includes the recent development. The description of this report is given.
Date: December 31, 1993
Creator: Ahmadi, Goodarz
Partner: UNT Libraries Government Documents Department

Developing Supersonic Impactor and Aerodynamic Lens for Separation and Handling of Nano-Sized Particles

Description: A computational model for supersonic flows of compressible gases in an aerodynamic lens with several lenses and in a supersonic/hypersonic impactor was developed. Airflow conditions in the aerodynamic lens were analyzed and contour plots for variation of Mach number, velocity magnitude and pressure field in the lens were evaluated. The nano and micro-particle trajectories in the lens and their focusing and transmission efficiencies were evaluated. The computational model was then applied to design of a aerodynamic lens that could generate focus particle beams while operating under atmospheric conditions. The computational model was also applied to airflow condition in the supersonic/hypersonic impactor. Variations of airflow condition and particle trajectories in the impactor were evaluated. The simulation results could provide understanding of the performance of the supersonic and hypersonic impactors that would be helpful for the design of such systems.
Date: June 30, 2008
Creator: Ahmadi, Goodarz
Partner: UNT Libraries Government Documents Department

Regional groundwater modeling of the saturated zone in the vicinity of Yucca Mountain, Nevada; Iterative Performance Assessment, Phase 2

Description: Results of groundwater modeling of the saturated zone in the vicinity of Yucca Mountain are presented. Both a regional (200 {times} 200 km) and subregional (50 {times} 50 km) model were used in the analyses. Simulations were conducted to determine the impact of various disruptive that might take place over the life span of a proposed Yucca Mountain geologic conditions repository on the groundwater flow field, as well as changes in the water-table elevations. These conditions included increases in precipitation and groundwater recharge within the regional model, changes in permeability of existing hydrogeologic barriers, a:nd the vertical intrusion of volcanic dikes at various orientations through the saturated zone. Based on the regional analysis, the rise in the water-table under Yucca Mountain due to various postulated conditions ranged from only a few meters to 275 meters. Results of the subregional model analysis, which was used to simulate intrusive dikes approximately 4 kilometers in length in the vicinity of Yucca Mountain, showed water-table rises ranging from a few meters to as much as 103 meters. Dikes oriented approximately north-south beneath Yucca Mountain produced the highest water-table rises. The conclusions drawn from this analysis are likely to change as more site-specific data become available and as the assumptions in the model are improved.
Date: October 1, 1992
Creator: Ahola, M. & Sagar, B.
Partner: UNT Libraries Government Documents Department

Inversion of Airborne Contaminants in a Regional Model

Description: We are interested in a DDDAS problem of localization of airborne contaminant releases in regional atmospheric transport models from sparse observations. Given measurements of the contaminant over an observation window at a small number of points in space, and a velocity field as predicted for example by a mesoscopic weather model, we seek an estimate of the state of the contaminant at the beginning of the observation interval that minimizes the least squares misfit between measured and predicted contaminant field, subject to the convection-diffusion equation for the contaminant. Once the ''initial'' conditions are estimated by solution of the inverse problem, we issue predictions of the evolution of the contaminant, the observation window is advanced in time, and the process repeated to issue a new prediction, in the style of 4D-Var. We design an appropriate numerical strategy that exploits the spectral structure of the inverse operator, and leads to efficient and accurate resolution of the inverse problem. Numerical experiments verify that high resolution inversion can be carried out rapidly for a well-resolved terrain model of the greater Los Angeles area.
Date: January 10, 2007
Creator: Akcelik, V.; Biros, G.; Draganescu, A.; Ghattas, O.; Hill, J.; van Bloemen Waanders, B. et al.
Partner: UNT Libraries Government Documents Department

The relation of solar wind structure to hydromagnetic discontinuities

Description: High resolution ISEE-3 data have been used to examine the relative abundances of tangential (TD) vs rotational (RD) discontinuities in different types of solar wind flow. Three types of flow were examined; flow from coronal holes, sector boundary flow and transient flow. It has been found that coronal hole flow has substantially more discontinuities and a greater ratio of RD's to TD's than do the other types of flow. Discontinuities are least frequent in transient flows characterized by bidirectional streaming of electrons. This leads us to the conclusion that meaningful studies of the velocity dependence of the rates of occurrence of different types of discontinuities must take the type of flow (coronal hole versus transient) into account. 7 refs., 3 figs., 1 tab.
Date: January 1, 1987
Creator: Alexander, C.J.; Neugebauer, M.; Smith, E.J. & Bame, S.J.
Partner: UNT Libraries Government Documents Department

Collection and analysis of existing data for waste tank mechanistic analysis. Progress report, December 1990

Description: Pacific Northwest Laboratory (PNL) is conducting this study for Westinghouse Hanford Company (Westinghouse Hanford), a contractor for the US Department of Energy (DOE). The purpose of the work is to study possible mechanisms and fluid dynamics contributing to the periodic release of gases from the double-shell waste storage tanks at the Hanford Site in Richland, Washington. The waste inside the tank is generating and periodically releasing potentially flammable gases into the tank`s vent system according to observations. Questions scientists are trying to answer are: (1) How are these gases generated? (2) How did these gases become trapped? (3) What causes the periodic gas releases? (4) And, what is the mechanism of the gas releases? To develop a safe mitigation strategy, possible physical mechanisms for the periodic release of flammable gases need to be understood. During initial work, PNL has obtained, correlated, analyzed, and compared data with expected physical properties, defined mechanisms; and prepared initial models of gas formation and retention. This is the second interim report summarizing the status of the work done to data.
Date: December 1, 1991
Creator: Allemann, R. T.; Antoniak, Z. I.; Friley, J. R.; Haines, C. E.; Liljegren, L. M. & Somasundaram, S.
Partner: UNT Libraries Government Documents Department

Collection and analysis of existing data for waste tank mechanistic analysis

Description: Pacific Northwest Laboratory (PNL) is conducting this study for Westinghouse Hanford Company (Westinghouse Hanford), a contractor for the US Department of Energy (DOE). The purpose of the work is to study possible mechanisms and fluid dynamics contributing to the periodic release of gases from the double-shell waste storage tanks at the Hanford Site in Richland, Washington. The waste inside the tank is generating and periodically releasing potentially flammable gases into the tank's vent system according to observations. Questions scientists are trying to answer are: (1) How are these gases generated (2) How did these gases become trapped (3) What causes the periodic gas releases (4) And, what is the mechanism of the gas releases To develop a safe mitigation strategy, possible physical mechanisms for the periodic release of flammable gases need to be understood. During initial work, PNL has obtained, correlated, analyzed, and compared data with expected physical properties, defined mechanisms; and prepared initial models of gas formation and retention. This is the second interim report summarizing the status of the work done to data.
Date: December 1, 1991
Creator: Allemann, R.T.; Antoniak, Z.I.; Friley, J.R.; Haines, C.E.; Liljegren, L.M. & Somasundaram, S.
Partner: UNT Libraries Government Documents Department

Geochemical modeling at Raft River

Description: Chemical analysis of water from three depth regimes at the Raft River KGRA indicate the presence of at least two distinct hydrothermal fluids. One fluid predominates in the fracture system on the west side of the valley, known as the Bridge Fault. This fluid is characterized by low conductivity (2,000 to 3,000 ..mu..s) and 6 to 9 ..mu..g/ml F/sup -/. The second fluid, encountered in the center of the valley, appears to be associated with the Narrows Structure and is characterized by a conductivity of 6,000 to 11,000 ..mu..s and F/sup -/ of 3 to 6 ..mu..g/ml. Contour mapping of conductivity and Cl/sup -//F/sup -/ ratios indicates upwelling of both deep geothermal fluids into the shallow system. This recharge into the intermediate and shallow zones produces high-conductivity water which is used for irrigation. Application of a simple mixing model shows that all the water sampled in intermediate and deep zones can be described by mixtures of two nearly pure fluids. One mechanism, consistent with the known data, is deep upwelling of a highly mineralized fluid which is heated by the basement rock and then penetrates sediment layers through fractures. The second fluid is relatively recent meteoric water conductively heated by the basement rock.
Date: January 1, 1979
Creator: Allen, C.A.; Chaney, R.E. & McAtee, R.E.
Partner: UNT Libraries Government Documents Department

Toward an extended-geostrophic Euler-Poincare model for mesoscale oceanographic flow

Description: The authors consider the motion of a rotating, continuously stratified fluid governed by the hydrostatic primitive equations (PE). An approximate Hamiltonian (L1) model for small Rossby number {var_epsilon} is derived for application to mesoscale oceanographic flow problems. Numerical experiments involving a baroclinically unstable oceanic jet are utilized to assess the accuracy of the L1 model compared to the PE and to other approximate models, such as the quasigeostrophic (QG) and the geostrophic momentum (GM) equations. The results of the numerical experiments for moderate Rossby number flow show that the L1 model gives accurate solutions with errors substantially smaller than QG or GM.
Date: July 1998
Creator: Allen, J. S.; Newberger, P. A. & Holm, D. D.
Partner: UNT Libraries Government Documents Department

Extension of SCDAP/RELAP5 severe accident models to non-LWR reactor designs. [Non-Light Water Reactors]

Description: The SCDAP/RELAP5 code has been extended to calculate the core melt progression and fission product transport that may occur in non-LWR reactors during severe accidents. The code's approach of connecting together according to user instructions all of the parts that constitute a reactor system give the code the capability to model a wide range of reactor designs. The models added to the code for analyses of non-LWR reactors include: (a) oxidation and melt progression in cores with U-Al based fuel elements, (b) movement of liquefied material from its original place in the core to other parts of the reactor systems, such as the outlet piping, (c) fission product release from U-Al based fuel and zinc release from aluminum, and (d) fission product release from a pool of molten core material. 9 refs., 5 figs.
Date: January 1, 1990
Creator: Allison, C.M.; Siefken, L.J.; Hagrman, D.L. (EG and G Idaho, Inc., Idaho Falls, ID (USA)) & Cheng, T.C. (Los Alamos National Lab., NM (USA))
Partner: UNT Libraries Government Documents Department