Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Language: English
    In: Environmental Earth Sciences, 2016, Vol.75(22), pp.1-13
    Description: Upward displacement of brine from deep geological formations poses a potential threat to near-surface drinking water resources. In this work, the impact of a layered sequence of hydraulically permeable and impermeable layers connected by a vertical fluid pathway like, e.g., a fault is investigated using an idealized scenario and numerical process simulation. Long-term upward brine migration is induced by overpressure in the lowest permeable formation, and the upward migration through the vertical pathway and the interaction with the intermediary permeable layers is investigated. The simulations show that brine displaced upwards through the vertical fluid pathway moves into the intermediary permeable formations, settling into the lower parts of the permeable layers and displacing the resident less salty formation brine from this layer further upwards through the vertical pathway. Thus, formation brine from different depths displaces each other rather than mixing along the pathway or rising along the full length of the vertical pathway. An effect of the gradual upward displacement is a decrease in the salt concentrations along the pathway such that brine intrusion into the groundwater aquifer is reduced. However, if the hydraulic connection between the vertical pathway and the intermediary layers is low, higher-density brine accumulates in the vertical pathway and upward movement of the brine is impeded due to its own weight.
    Keywords: Thermohaline simulation ; Brine migration ; Permeable fault ; Deep underground injection ; Salt intrusion
    ISSN: 1866-6280
    E-ISSN: 1866-6299
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: Environmental Earth Sciences, 2013, Vol.69(2), pp.395-414
    Description: This work introduces the soil air system into integrated hydrology by simulating the flow processes and interactions of surface runoff, soil moisture and air in the shallow subsurface. The numerical model is formulated as a coupled system of partial differential equations for hydrostatic (diffusive wave) shallow flow and two-phase flow in a porous medium. The simultaneous mass transfer between the soil, overland, and atmosphere compartments is achieved by upgrading a fully established leakance concept for overland-soil liquid exchange to an air exchange flux between soil and atmosphere. In a new algorithm, leakances operate as a valve for gas pressure in a liquid-covered porous medium facilitating the simulation of air out-break events through the land surface. General criteria are stated to guarantee stability in a sequential iterative coupling algorithm and, in addition, for leakances to control the mass exchange between compartments. A benchmark test, which is based on a classic experimental data set on infiltration excess (Horton) overland flow, identified a feedback mechanism between surface runoff and soil air pressures. Our study suggests that air compression in soils amplifies surface runoff during high precipitation at specific sites, particularly in near-stream areas.
    Keywords: Coupled flow ; Two-phase flow ; Horton runoff ; Leakance ; Soil gas release ; OpenGeoSys (OGS)
    ISSN: 1866-6280
    E-ISSN: 1866-6299
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Acta Geotechnica, 2014, Vol.9(1), pp.81-86
    Description: In geological formations, migration of CO 2 plume is very complex and irregular. To make CO 2 capture and storage technology feasible, it is important to quantify CO 2 amount associated with possible leakage through natural occurring faults and fractures in geologic medium. Present work examines the fracture aperture effect on CO 2 migration due to free convection. Numerical results reveal that fracture with larger-aperture intensify CO 2 leakage. Mathematical formulation and equations of state for the mixture are implemented within the object-oriented finite element code OpenGeoSys developed by the authors. The volume translated Peng–Robinson equation of state is used for material properties of CO 2 and water.
    Keywords: Fracture ; OpenGeoSys ; Free convection ; Sorption ; Leakage ; Translated volume
    ISSN: 1861-1125
    E-ISSN: 1861-1133
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: Environmental Earth Sciences, 2012, Vol.65(5), pp.1439-1457
    Description: This paper presents the hydrological coupling of the software framework OpenGeoSys (OGS) with the EPA Storm Water Management Model (SWMM). Conceptual models include the Saint Venant equation for river flow, the 2D Darcy equations for confined and unconfined groundwater flow, a two-way hydrological coupling flux in a compartment coupling approach (conductance concept), and Lagrangian particles for solute transport in the river course. A SWMM river–OGS aquifer inter-compartment coupling flux is examined for discharging groundwater in a systematic parameter sensitivity analysis. The parameter study involves a small perturbation (first-order) sensitivity analysis and is performed for a synthetic test example base-by-base through a comprehensive range of aquifer parametrizations. Through parametrization, the test cases enables to determine the leakance parameter for simulating streambed clogging and non-ocillatory river-aquifer water exchange rates with the sequential (partitioned) coupling scheme. The implementation is further tested with a hypothetical but realistic 1D river–2D aquifer model of the Poltva catchment, where discharging groundwater in the upland area affects the river–aquifer coupling fluxes downstream in the river course (propagating feedbacks). Groundwater contribution in the moving river water is numerically determined with Lagrangian particles. A numerical experiment demonstrates that the integrated river–aquifer model is a serviceable and realistic constituent in a complete compartment model of the Poltva catchment.
    Keywords: Integrated surface–subsurface flow modelling ; Urban water ; Conductance concept ; Sensitivity analysis ; Random walk particle tracking (RWPT) ; Poltva basin (Western Ukraine)
    ISSN: 1866-6280
    E-ISSN: 1866-6299
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: English
    In: Acta Geotechnica, 2014, Vol.9(1), p.81(6)
    Description: Byline: Ashok Singh (1), Jens Olaf Delfs (1,2), Uwe Jens Gorke (1), Olaf. Kolditz (1,3) Keywords: Fracture; OpenGeoSys; Free convection; Sorption; Leakage; Translated volume Abstract: In geological formations, migration of CO.sub.2 plume is very complex and irregular. To make CO.sub.2 capture and storage technology feasible, it is important to quantify CO.sub.2 amount associated with possible leakage through natural occurring faults and fractures in geologic medium. Present work examines the fracture aperture effect on CO.sub.2 migration due to free convection. Numerical results reveal that fracture with larger-aperture intensify CO.sub.2 leakage. Mathematical formulation and equations of state for the mixture are implemented within the object-oriented finite element code OpenGeoSys developed by the authors. The volume translated Peng--Robinson equation of state is used for material properties of CO.sub.2 and water. Author Affiliation: (1) Helmholtz Centre for Environmental Research-UFZ, Permoserstr. 15, 04318, Leipzig, Germany (2) Water and Earth System Science Research Centre (WESS), Keplerstrasse 17, 72074, Tubingen, Germany (3) University of Technology Dresden, Dresden, Germany Article History: Registration Date: 25/02/2013 Received Date: 25/01/2013 Accepted Date: 25/02/2013 Online Date: 05/05/2013
    Keywords: Fracture (Materials)
    ISSN: 1861-1125
    Source: Cengage Learning, Inc.
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: Environmental Earth Sciences, 2014, Vol.72(10), pp.3827-3837
    Description: This paper evaluates the remediation potential of a salinized coastal aquifer by utilizing a scenario simulation. Therefore, the numerical model OpenGeoSys is first validated against analytical and experimental data to represent transient groundwater level development and variable density saline intrusion. Afterwards, a regional scale model with a three-dimensional, heterogeneous hydrogeology is calibrated for a transient state and used to simulate a best-case scenario. Water balances are evaluated in both the transient calibration and scenario run. Visualization techniques help to assess the complex model output providing valuable insight in the occurring density-driven flow processes. Furthermore, modeling and visualization results give information on the time scale for remediation activities and, due to limitations in data quality and quantity reveal potential for model improvement.
    Keywords: Groundwater modeling ; Density-dependent ; Saltwater intrusion ; OpenGeoSys ; Model validation benchmark ; Transient calibration ; Scenario simulation ; Remediation potential ; Visualization
    ISSN: 1866-6280
    E-ISSN: 1866-6299
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: Environmental Earth Sciences, 11/2014, Vol.72(10), pp.3827-3837
    Description: This paper evaluates the remediation potential of a salinized coastal aquifer by utilizing a scenario simulation. Therefore, the numerical model OpenGeoSys is first validated against analytical and experimental data to represent transient groundwater level development and variable density saline intrusion. Afterwards, a regional scale model with a three-dimensional, heterogeneous hydrogeology is calibrated for a transient state and used to simulate a best-case scenario. Water balances are evaluated in both the transient calibration and scenario run. Visualization techniques help to assess the complex model output providing valuable insight in the occurring density-driven flow processes. Furthermore, modeling and visualization results give information on the time scale for remediation activities and, due to limitations in data quality and quantity reveal potential for model improvement. Copyright 2014 Springer-Verlag Berlin Heidelberg
    Keywords: Hydrogeology ; Environmental Geology ; Applications ; Aquifers ; Coastal Environment ; Computer Programs ; Data Processing ; Ground Water ; Numerical Models ; Opengeosys ; Pollution ; Remediation ; Salt Water ; Salt-Water Intrusion ; Simulation ; Three-Dimensional Models ; Visualization ; Water Pollution;
    ISSN: 1866-6280
    E-ISSN: 1866-6299
    Source: Springer (via CrossRef)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: Energy Procedia, 2013, Vol.40, pp.481-489
    Description: Current research into CO2 capture and storage is dominated by improving the CO2 storage capacity. In this context, risk related to CO2 leakage is an important issue which may cause environmental problems, particularly when freshwater resources nearby are intruded by the CO2 plume. In this work, the leakage into a multi-layered fractured saline aquifer is modelled with a numerical model regarding its pressure build-up process. The investigation is performed with the non-isothermal compositional fluid flow module implemented by authors in the OpenGeoSys (OGS) software for geotechnical applications.
    Keywords: Pressure Build-Up ; Saline Aquifer ; Fracture ; Sorption ; Multi-Componential ; Opengeosys ; Non-Isothermal ; Gelerkin ; Engineering ; Economics
    ISSN: 1876-6102
    E-ISSN: 1876-6102
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Language: English
    In: Environmental Earth Sciences, 2012, Vol.65(5), pp.1367-1380
    Description: Numerical modeling of interacting flow and transport processes between different hydrological compartments, such as the atmosphere/land surface/vegetation/soil/groundwater systems, is essential for understanding the comprehensive processes, especially if quantity and quality of water resources are in acute danger, like e.g. in semi-arid areas and regions with environmental contaminations. The computational models used for system and scenario analysis in the framework of an integrated water resources management are rapidly developing instruments. In particular, advances in computational mathematics have revolutionized the variety and the nature of the problems that can be addressed by environmental scientists and engineers. It is certainly true that for each hydro-compartment, there exists many excellent simulation codes, but traditionally their development has been isolated within the different disciplines. A new generation of coupled tools based on the profound scientific background is needed for integrated modeling of hydrosystems. The objective of the IWAS-ToolBox is to develop innovative methods to combine and extend existing modeling software to address coupled processes in the hydrosphere, especially for the analysis of hydrological systems in sensitive regions. This involves, e.g. the provision of models for the prediction of water availability, water quality and/or the ecological situation under changing natural and socio-economic boundary conditions such as climate change, land use or population growth in the future.
    Keywords: Coupling ; Modeling ; Surface–subsurface ; Soil–root water flow ; Reactive transport ; Density-dependent flow
    ISSN: 1866-6280
    E-ISSN: 1866-6299
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    In: Water Resources Research, February 2014, Vol.50(2), pp.1531-1549
    Description: There are a growing number of large‐scale, complex hydrologic models that are capable of simulating integrated surface and subsurface flow. Many are coupled to land‐surface energy balance models, biogeochemical and ecological process models, and atmospheric models. Although they are being increasingly applied for hydrologic prediction and environmental understanding, very little formal verification and/or benchmarking of these models has been performed. Here we present the results of an intercomparison study of seven coupled surface‐subsurface models based on a series of benchmark problems. All the models simultaneously solve adapted forms of the Richards and shallow water equations, based on fully 3‐D or mixed (1‐D vadose zone and 2‐D groundwater) formulations for subsurface flow and 1‐D (rill flow) or 2‐D (sheet flow) conceptualizations for surface routing. A range of approaches is used for the solution of the coupled equations, including global implicit, sequential iterative, and asynchronous linking, and various strategies are used to enforce flux and pressure continuity at the surface‐subsurface interface. The simulation results show good agreement for the simpler test cases, while the more complicated test cases bring out some of the differences in physical process representations and numerical solution approaches between the models. Benchmarks with more traditional runoff generating mechanisms, such as excess infiltration and saturation, demonstrate more agreement between models, while benchmarks with heterogeneity and complex water table dynamics highlight differences in model formulation. In general, all the models demonstrate the same qualitative behavior, thus building confidence in their use for hydrologic applications. Seven hydrologic models were intercompared on standard benchmark problems In general, though there are differences in approach, these models agree Model differences can be attributed to solution technique and coupling strategy
    Keywords: Model Intercomparison
    ISSN: 0043-1397
    E-ISSN: 1944-7973
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages