Civil Engineering / İnşaat Mühendisliği

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End date: 1999Subject: search.filters.subject.Porous media

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  • Article
    Citation - WoS: 12
    Citation - Scopus: 12
    Oil Mound Spreading and Migration With Ambient Groundwater Flow in Coarse Porous Media
    (John Wiley and Sons Inc., 1996) Çorapçıoplu, M. Yavuz; Tuncay, Kağan; Ceylan, B. Kağan
    When a light, immiscible oil leaks above an unconfined aquifer, it spreads and forms a floating mound on the table. The oil mound migrates in the direction of ambient ground flow. In this study we present a governing equation for the migrating mound thickness by averaging the oil phase mass balance equation. Analytical and numerical solutions to an advective- dispersive type equation are presented to estimate the temporal and spatial distribution of the migrating oil mound thickness for two problems of practical importance: formation, spreading, and migration of an oil mound on the table and spreading and migration of an established layer of oil with ambient ground flow. The model results compare favorably with test data obtained by laboratory flume experiments. Although the model has some simplifying assumptions such as the absence of capillary pressure gradients, sharp saturation changes across the phase interfaces, and single mobile phase (i.e., oil flow only), it can be useful as a screening or site assessment tool because of its relative simplicity.
  • Article
    Citation - WoS: 75
    Citation - Scopus: 82
    Body Waves in Poroelastic Media Saturated by Two Immiscible Fluids
    (John Wiley and Sons Inc., 1996) Tuncay, Kağan; Çorapçıoğlu, M. Yavuz
    A study of body waves in elastic porous media saturated by two immiscible Newtonian fluids is presented. We analytically show the existence of three compressional waves and one rotational wave in an infinite porous medium. The first and second compressional waves are analogous to the fast and slow compressional waves in Biot's theory. The third compressional wave is associated with the pressure difference between the fluid phases and dependent on the slope of capillary pressure-saturation relation. Effect of a second fluid phase on the fast and slow waves is numerically investigated for Massillon sandstone saturated by air and water phases. A peak in the attenuation of the first and second compressional waves is observed at high water saturations. Both the first and second compressional waves exhibit a drop in the phase velocity in the presence of air. The results are compared with the experimental data available in the literature. Although the phase velocity of the first compressional and rotational waves are well predicted by the theory, there is a discrepancy between the experimental and theoretical values of attenuation coefficients. The causes of discrepancy are explained based on experimental observations of other researchers.
  • Article
    Citation - Scopus: 42
    Propagation of Waves in Porous Media
    (Elsevier Ltd., 1996) Çorapçıoplu, M. Yavuz; Tuncay, Kağan
    Wave propagation in porous media is of interest in various diversified areas of science and engineering. The theory of the phenomenon has been studied extensively in soil mechanics, seismology, acoustics, earthquake engineering, ocean engineering, geophysics, and many other disciplines. This review presents a general survey of the literature within the context of porous media mechanics. Following a review of the Biot's theory of wave propagation in linear, elastic, fluid saturated porous media which has been the basis of many analyses, we present various analytical and numerical solutions obtained by several researchers. Biot found that there are two dilatational waves and one rotational wave in a saturated porous medium. It has been noted that the second kind of dilatational wave is highly attenuated and is associated with a diffusion type process. The influence of coupling between two phases has a decreasing effect on the first kind wave and an increasing effect on the second wave. Procedures to predict the liquefaction of soils due to earthquakes have been reviewed in detail. Extension of Biot's theory to unsaturated soils has been discussed, and it was noted that, in general, equations developed for saturated media were employed for unsaturated media by replacing the density and compressibility terms with modified values for a water-air mixture. Various approaches to determine the permeability of porous media from attenuation of dilatational waves have been described in detail. Since the prediction of acoustic wave speeds and attenuations in marine sediments has been extensively studied in geophysics, these studies have been reviewed along with the studies on dissipation of water waves at ocean bottoms. The mixture theory which has been employed by various researchers in continuum mechanics is also discussed within the context of this review. Then, we present an alternative approach to obtain governing equations of wave propagation in porous media from macroscopic balance equations. Finally, we present an analysis of wave propagation in fractured porous media saturated by two immiscible fluids.