Jacob Bear - Academia.edu (original) (raw)

Papers by Jacob Bear

Journal of the Hydraulics Division, 1965

Transport in Porous Media, 1992

A lumped parameter, seven-compartmental model for the cerebrovascular fluid system is constructed... more A lumped parameter, seven-compartmental model for the cerebrovascular fluid system is constructed and solved for the quasi-steady state flow. The model predicts the pressure waves in the various compartments of the intracraniaZ reqiun in r'c.;Ponc to changes in the artcrial pressui,'.

Con tamin an t Diffusion UCRL-ID-115626 The approved alternative for ground water remediation inv... more Con tamin an t Diffusion UCRL-ID-115626 The approved alternative for ground water remediation involves extracting and treating ground water at a number of initial locations (DOE, 1992). Extraction wells would be strategically installed to control the spread of VOCs from the currently contaminated ed area in concentrations above Maximum Contaminant Levels (MCLs). Based on the Remedial Investigation and Feasibility Study analyses, and codified in the Record of Decision (DOE, 1992), the DOE, LLNL, U.S. EPA, California EPA Department of Toxic Substances Control (DTSC), and the California Regional Water Quality Control Board (RWQCB) believe that the preferred alternatives for cleaning the saturated zone fully satisfy the nine EPA evaluation criteria (EPA, 1988). Although more expensive in the short-run, the preferred cleanup alternatives satisfy the State's Applicable or Relevant and Appropriate Requirements (ARARs) for nondegradation of ground water resources, reduce the mobility of the contaminants, provide a permanent solution, utilize alternative treatment technologies to the maximum extent practicable, and will achieve cleanup faster than other alternatives. The hydrogeologic conditions found at LLNL have had and will continue to have influence on the choice of cleanup and operational strategies.

Engineering Geology, 1982

Canadian Geotechnical Journal, 1988

Water Resources Research, 1981

A mathematical model for regional land subsidence has been developed by employing Terzaghi's... more A mathematical model for regional land subsidence has been developed by employing Terzaghi's concept of effective stress and assuming vertical solid compressibility only. First the groundwater mass conservation equation in a compressible aquifer is developed for a ...

Field carbon dioxide injection experiments are necessary for demonstration, increasing the scient... more Field carbon dioxide injection experiments are necessary for demonstration, increasing the scientific understanding and quantification of the relevant processes occurring during geological storage in deep saline aquifers. As part of the large scale EU-FP7 project MUSTANG, a carbon dioxide injection experiment is to be carried out at the Heletz site, Israel. Estimating the well head conditions is an important part of planning the experiment and an approach is presented here for determining wellhead conditions needed to ensure that at least a specified flow rate is provided to the formation, given target layer conditions, while still respecting pressure buildup constraints. The main part of the study combines the multiphase flow in the target layer using the well known TOUGH2/ECO2N model, with the flow in the injection pipe solving the 1D steady, real gas, augmented Euler equation. The Matching is carried on in a two-stage process.The second part consists of a transient simulation of ...

Eos, Transactions American Geophysical Union, 1983

Transport of quantities such as mass component of a phase and/or heat occurs in fields as diversi... more Transport of quantities such as mass component of a phase and/or heat occurs in fields as diversified as petroleum reservoir engineering, groundwater hydraulics, soil mechanics, industrial filtration, water purification, wastewater treatment, soil drainage and irrigation, and geothermal energy production. In all these areas, scientists, engineers, and planners make use of mathematical models; these models describe the relevant transport processes that occur within controlled porous medium domains and enable forecasting of the future behavior of these domains in response to planned activities. The mathematical models, in turn, are based on the understanding of phenomena, often within the void space, and on theories that relate these phenomena to measurable quantities.Because of the pressing needs in areas of practical interest such as the development of groundwater energy storage and geothermal energy production, a vast amount of research in all these fields has contributed, especially in the last two decades, to our understanding and ability to describe transport phenomena in porous media. In recent years these research efforts have been significantly accelerated, attracting scientists from many disciplines. The practical needs of solving boundary value problems in heterogeneous domains, irregular boundaries, coupled phenomena and multiple dependent variables led to the development of a variety of powerful numerical techniques. The realization that fields are highly heterogeneous and that the degree of heterogeneity depends on the scale of the problem led to the introduction of stochastic concepts as an additional tool for the description of phenomena.

Introduction to Modeling of Transport Phenomena in Porous Media, 1990

Phenomena of transport in porous media are encountered in many engineering disciplines. Civil eng... more Phenomena of transport in porous media are encountered in many engineering disciplines. Civil engineering deals, for example, with the flow of water in aquifers, the movement of moisture through and under engineering structures, transport of pollutants in aquifers and the propagation of stresses under foundations of structures. Agricultural engineering deals, for example, with the movement of water and solutes in the root zone in the soil. Heat and mass transport in packed-bed reactor columns and drying processes are encountered in chemical engineering. Reservoir engineers deal with the flow of oil, water and gets in petroleum reservoirs. In all these examples, one or more extensive quantities (i.e., quantities that are additive over volumes, with mass, momentum and energy as examples) are transported through the solid and/or the fluid phases that together occupy a porous medium domain. To solve a problem of transport in such a domain means to determine the spatial and temporal distributions of state variables (e.g., velocity, mass density and pressure of a fluid phase, concentration of a solute, stress in the solid skeleton), that have been selected to describe the state of the material system occupying that domain.

2002 Chicago, IL July 28-31, 2002, 2002

ABSTRACT A model has been developed to describe Nitrogen and organic Carbon transformations in so... more ABSTRACT A model has been developed to describe Nitrogen and organic Carbon transformations in soil aggregates. The proposed model extends previously published models of radial diffusion by considering the processes that lead up to the development of conditions suitable for denitrification to occur. In particular, the model considers the situation where the soil is irrigated with treated wastewater – effluent. It is demonstrated how the model can be applied to perform sensitivity analyses of parameters that are known only with high uncertainty. Presented results illustrate the models’ capability to reproduce results from previous models with respect to the prediction of the anaerobic volumetric fraction. Nitrogen species fluxes from the aggregate are consistent with the kinetic model chosen; an incoherency in the determination of the denitrification parameters impede the results obtained form that sub-model and requires attention prior to the implementation of the aggregate model in a soil profile model.

Nitrogen dynamics in the soil under the condition of environmentally friendly fertilization pract... more Nitrogen dynamics in the soil under the condition of environmentally friendly fertilization practices (EFFPs) is described by a comprehensive N-dynamics model. The model (first paper of this series, Transport in Porous Media 31(3) (1998), 249-274) is different from other models in its capability of simulating the special phenomena related to the application of EFFPs. In this paper, a finite difference method is used to solve the mathematical model. The numerical model is verified by simulating several water flow and conservative solute transport problems with existing numerical or analytic solutions. The good agreements between our simulation results and the solutions given by others show that our model is reliable in simulating flow and transport problems in the soil. Preliminary model validation is conducted by applying the model to simulate two field experiments. The acceptable agreements between our numerical simulation results and experimental data demonstrate that the model can reasonably model N-dynamics in the soil under field conditions.

Water Resources Research, 1983

A mathematical model is developed for the areal distribution of drawdown, land subsidence, and ho... more A mathematical model is developed for the areal distribution of drawdown, land subsidence, and horizontal displacements due to groundwater pumping from a deformable phreatic aquifer. This paper is a continuation of earlier works published by the authors (Bear and Corapcioglu, 1981a, b) on the subject of regional land subsidence due to pumping in confined and leaky aquifers. All the basic assumptions underlying these previous works are also valid here. However, in this case the same methodology is extended to the case of a phreatic aquifer. The main additional feature in the present paper is that due to the decline of the water table, the total stress at points within the flow domain changes continuously. Following the development of a three-dimensional mathematical model consisting of a mass conservation equation, quasi-static equilibrium equations, and stress-strain relations for an assumed perfectly elastic solid matrix, a regional, horizontal two-dimensional model is derived by averaging the three-dimensional model over the vertical thickness of the aquifer, taking into account the continuous variation in total stress as a result of water table fluctuations. The separation of an initially coinciding phreatic surface, which serves as the upper boundary of the aquifer, and a surface consisting of a set of solid particles during the lowering of the water table and the compaction of the aquifer has been incorporated into the averaging procedure. An analytical solution is given for the case of a single pumping well. The solution, which is expressed in terms of the classical well function for a confined aquifer but with a modified storativity, provides estimates of drawdown, vertical subsidence, and horizontal displacement. The displacements for a sample problem are compared with those of a confined aquifer under similar conditions. The results indicate that under the conditions of the studied case of radial flow, vertical and horizontal displacements due to pumping from a phreatic aquifer with the same discharge rate would be less than those of a confined one. Furthermore, the same averaging procedure is extended for a system of phreatic and leaky confined aquifers and for the unsaturated zone above the water table. An additional change in total stress is obtained in terms of moisture content of the zone above the phreatic surface.

Transport in Porous Media, 2009

The objective of this article is to highlight certain features of a number of coefficients that a... more The objective of this article is to highlight certain features of a number of coefficients that appear in models of phenomena of transport in anisotropic porous media, especially the coefficient of dispersion, the 2nd rank tensor D ij , and the dispersivity coefficient, the 4th rank tensor a ijkl , that appear in models of solute transport. Although we shall focus on the transport of mass of a dissolved chemical species in a fluid phase that occupies the void space, or part of it, the same discussion is also applicable to transport coefficients that appear in models that describe the advective mass flux of a fluid and the diffusive transport of other extensive quantities, like heat. The case of coupled processes, e.g. the simultaneous transport of heat and mass of a chemical species, are also considered. The entire discussion will be at the macroscopic level, at which a porous medium domain is visualized as homogenized continuum.

Transport in Porous Media, 1994

Journal of Hydrology, 1965

The paper deals with artificial replenishment through wells and with the movement of water bodies... more The paper deals with artificial replenishment through wells and with the movement of water bodies injected into confined aquifers. The knowledge of such movement is essential for any planning of artificial replenishment of ground water aquifers, both for storage and for mixing purposes. The assumption underlying the present investigations is that the native water in the aquifer and the injected water are two immiscible liquids of different salinities. It is also assumed that differences in density and viscosity are small and may be neglected. Two cases have been investigated: (1) injection through a single well under steady flow conditions into a confined aquifer in which uniform flow takes place, and (2) the movement of injected water bodies under nonsteady flow conditions. In addition to the determination of front shapes, the recovery ratio of injected water in the water pumped through the same well and the extent of mixing in the pumped water, were determined.

Journal of Geophysical Research, 1964

The hodograph method is used to study the shape and position of the interface between two immisei... more The hodograph method is used to study the shape and position of the interface between two immiseible liquids of different densities when the heavier liquid is at rest. The principles of the method are briefly reviewed. Four cases are presented: (a) An interface in a confined aquifer, (b) upconing toward a sink in an unbounded aquifer, (c) upconing toward a sink in a confined aquifer of infinite thickness, and (d) a drain above the interface in an aquifer of infinite depth. The shape of the interface in each case is presented in the form of an equation and graphs. It is shown that in cases (a) and (c) the approximate solution based on the Dupuit assumption is, under certain conditions, sufficiently accurate.