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  • 1
    Electronic Resource
    Electronic Resource
    Thermal conductivity of random media and regular fractals (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 3872-3883 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The Laplace equation can be solved in any two- and three-dimensional porous medium by means of a vectorized numerical code. It is applied to several structures such as random media derived from site percolation; close to the percolation threshold, the critical exponents are found to be very close to the ones corresponding to networks; the results are usefully compared to previous variational upper bounds and to the prediction of an approximate space renormalization. Media with double porosity such as catalyst pellets are also addressed. Finally the conductivity of most fractals is shown to follow an Archie's law in the limit of large generation numbers; the exponents of the power laws can be retrieved by various renormalization arguments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346274
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  • 2
    Electronic Resource
    Electronic Resource
    Taylor dispersion in porous media. Determination of the dispersion tensor (1993)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 5 (1993), S. 2348-2376 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In homogeneous porous media, the analytical expression of the dispersion tensor D* can be calculated by the method of moments and by a multiple scale expansion; the symmetric component of this tensor is identical in both cases. Numerically, D* can be computed by two methods, namely the B equation and random walks. The porous media are modeled as being spatially periodic; D* is determined as a function of the Péclet number for four types of unit cells: deterministic, fractal, random, and reconstructed. A systematic comparison is made with existing numerical and experimental data. The long time behavior, and its Gaussian limit, is documented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.858751
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Bounds on the effective properties of polydispersed suspensions of spheres: An evaluation of two relevant morphological parameters (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 6088-6098 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Expressions for the two microstructural parameters that appear in the variational third-order bounds [G. W. Milton, Phys. Rev. Lett. 46, 542 (1981)] for the effective conductivity and elastic moduli of composite media are derived analytically to first order in the sphere concentration c for random well-mixed dispersions of impenetrable spheres with an arbitrary size distribution. These relations lead to rigorous bounds on the effective properties which are exactly valid to order c2 for such models. The apparent linear behavior of the microstructural parameters up to moderately high c enables one to apply the bounds beyond second-order in c, however. Employing these results, the effect of polydispersivity on the effective properties is examined. It is worth noting that, under some conditions, polydispersivity can actually lead to a slight decrease of the shear modulus, whereas, for highly conducting particles, polydispersivity always increases the effective conductivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.345169
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Measurement of two-dimensional velocity fields in porous media by particle image displacement velocimetry (1992)
    Springer
    Experiments in fluids 12 (1992), S. 210-212 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Local measurements of the phase function and of two components of the velocity can be performed in transparent porous media by means of particle image displacement velocimetry (P.I.D.V.). Some preliminary results are presented and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00188261
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  • 5
    Electronic Resource
    Electronic Resource
    Measurements of thermally-induced convection in a model porous medium (1995)
    Springer
    Flow, turbulence and combustion 55 (1995), S. 245-259 
    Details
    ISSN: 1573-1987
    Keywords: thermal convection ; porous medium ; Particle Image Velocimetry (PIV) ; Laser Doppler Anemometry (LDA)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The velocity field generated by thermal convection in a model porous medium is experimentally determined by means of both PIV and LDA techniques. Details of matching refraction index under non isothermal conditions are given. Fields are measured in the empty parallelepipedic cell and in a model medium made of parallel circular bundles. Results are in good agreement. Moreover, by an averaging technique, we are able to measure seeping velocity profiles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00867514
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  • 6
    Electronic Resource
    Electronic Resource
    Thermal Conductivity of a Single Fracture (1997)
    Springer
    Transport in porous media 27 (1997), S. 305-326 
    Details
    ISSN: 1573-1634
    Keywords: fracture ; conductivity ; self-affine.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract The macroscopic conductivity of fractures is determined for Gaussian and self-affine fractures by solving the three-dimensional Laplace equation. Results are discussed and compared with various analytical or two-dimensional approximations. They are shown to be in good agreement with some existing experimental data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006585510976
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  • 7
    Electronic Resource
    Electronic Resource
    Fractal porous media (1993)
    Springer
    Transport in porous media 13 (1993), S. 41-78 
    Details
    ISSN: 1573-1634
    Keywords: Fractal ; permeability ; conductivity ; transports
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract The transport properties of continuous deterministic fractals are reviewed. The method of construction, the fractal dimension, and the major features of transport are summarized. Then the major single-phase transports are addressed; attention is focused on the numerical results and on the analytical arguments which may be used to derive these results in a simple way, whenever it is possible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00613270
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    Flow along porous media by partical image velocimetry (1993)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 39 (1993), S. 1765-1776 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Velocity measurements near porous media are performed by particle image velocimetry. Fully established laminar flows along flat media are studied and compared with the predictions of classical models. Five types of porous media are investigated. Two-dimensional pictures of the flow, average velocities, and local fluctuations are discussed.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690391104
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  • 9
    Electronic Resource
    Electronic Resource
    NMR measurements and numerical simulation of fluid transport in porous solids (1997)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 43 (1997), S. 1653-1661 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pulsed magnetic field gradient stimulated echo NMR measurements are performed for diffusion and flow of an aqueous phase both within a sample of packed spherical beads and within a 25% porosity Fontainebleau sandstone. The stimulated echo dependence on the gradient pulse area q is used to derive the displacement probability distributions PΔ(X) for fixed observation times Δ. The shape of PΔ(X) as a function of Δ is simulated for computer-generated porous media, and a good agreement is obtained between the experimental NMR data and the simulations.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690430702
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