Porous media numerical solution

Associated with the mass balance of water and the mechanical equilibrium equation, relations (7) and (8) give a model of solution transport in a deformable porous medium. The result of an incremental numerical method was... 

Very briefly, the Dave model considers a force balance on a porous medium (the fiber bed). The total force from the autoclave pressure acting on the medium is countered by both the force due to the spring-like behavior of the fiber network and the hydrostatic force due to the liquid resin pressure within the porous fiber bed. Borrowing from consolidation theories developed for the compaction of soils 22 23), the Dave model describes one-dimensional consolidation with three-dimensional Darcy s Law flow. Numerical solutions were in excellent agreement with closed-form solutions for one- and two-dimensional resin flow cases in which the fiber bed permeabilities and compressibility, as well as the autoclave pressure, are all held constant21). 

To obtain numerically the mass transfer coefficient, a porous medium is stochastically constructed in the form of a sphere pack. Specifically, the representation of the biphasic domains under consideration is achieved by the random deposition of spheres of radius Rina box of length L. The structure is digitized and the phase function (equal to zero for solid and unity for the pore space) is determined in order to obtain the porosity and to solve numerically the convection- diffusion problem. The next for this purpose is to obtain the detailed flow field in the porous domain through the solution of the Stokes equations ... 

Soil structure, antecedent soil moisture and input flow rate control rapid flow along preferential pathways in well-structured soils. The amount of preferential flow may be significant for high input rates, mainly in the intermediate to high ranges of moisture. We use a three-dimensional lattice-gas model to simulate infiltration in a cracked porous medium as a function of rainfall intensity. We compute flow velocities and water contents during infiltration. The dispersion mechanisms of the rapid front in the crack are analyzed as a function of rainfall intensity. The numerical lattice-gas solutions for flow are compared with the analytical solution of the kinematic wave approach. The process is better described by the kinematic wave approach for high input flow intensities, but fails to adequately predict the front attenuation showed by the lattice-gas solution. 

No analytical solution is available for the modified Brinkman momentum equation (Eq. 13), which can only be solved numerically. However, due to the low Reynolds number flow in the microcapillaries, we can safely ignore the high Reynolds number term, i.e., pF4>u / /K 0. To emphasize only the electrokinetic wall effect, we can further assume that the porosity is uniform in the porous medium, i.e., cj) = Under these... 

Contaminants with very low water solubilities (e.g. polycyclic aromatic hydrocarbons) play an important role in risk assessment of dangerous wastes and development of soil remediation. The mobility of such hydrophobic substances can be strongly affected by the existence of carriers (e.g. dissolved organic carbon), which can adsorb the contaminant and thereby enhance or reduce its velocity. The numerical simulation of the spreading of these contaminants, requires the solution of reactive transport equations for all involved components, coupled by the contaminant s sorption to the carrier. Our development is based on a model [2], in which all the carrier s influence on the contaminant transport is contained in an effective adsorption isotherm, depending on the carrier concentration and thereby also on space and time. First we shortly summarize the modelling of reactive transport of a single component (carrier, contaminant, carrier bound contaminant) in a porous medium, then in section 3 we combine the two equations for the contaminant components. The properties of the contaminant s effective isotherm and its influence on the transport equation are discussed in section 4. 

Of the numerous methods developed to pack stationary porous medium/column in a microcapillary, two widely used approaches involve the packed beads column and the in situ polymerized monolithic column [5]. The preparation of the packed beads column includes the fabrication of retaining frits within a microcapillary as well as subsequent packing of micro-sized silica particles into the capillary. To avoid the problems associated with frit formation and bead packing, an alternative method is to prepare the monolithic column by performing in situ silicate- or photo-pol3mierization within a capillary using either thermal or UV initialization of pol)mier mixture solutions. 

A numerical model was developed to simulate MeBr movement in soil and volatilization into the atmosphere. The model simultaneously solves partial differential equations for nonlinear transport of water, heat, and solute in a variably saturated porous medium. Henry s Law is used to express partitioning between the liquid and gas phases and both liquid and vapor diffusion are included in the simulation. Soil degradation is simulated using a first-order decay reaction and the rate coefficients may differ in each of the three phases (i.e., liquid, solid, or gaseous). 

The numerical simulation of single-phase fluid flow in fibrous porous medium is considered in this paper. The object of the study is the square domain which includes 4 cylinders (see Fig. 1). Planar flow that perpendicular to the axes of cylinders is considered in this paper. This model is based on the numerical solution of the Navier-Stokes equations for incompressible fluid flow ... 

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