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dc.contributor.advisorTilton, Nils
dc.contributor.authorKhalifa, Zahra
dc.date.accessioned2020-07-06T10:04:44Z
dc.date.accessioned2022-02-03T13:20:47Z
dc.date.available2021-07-03T10:04:44Z
dc.date.available2022-02-03T13:20:47Z
dc.date.issued2020
dc.identifierKhalifa_mines_0052E_11983.pdf
dc.identifierT 8959
dc.identifier.urihttps://hdl.handle.net/11124/174202
dc.descriptionIncludes bibliographical references.
dc.description2020 Summer.
dc.description.abstractThough steady fluid flow through porous media is relatively well understood, fundamental questions remain for the case of unsteady fluid flow through porous media. Such flows occur in many environmental, industrial, and bio-mechanical applications. Examples include the turbulent atmospheric boundary layer over a forest canopy, enhanced oil recovery, and wave interactions with permeable coastal structures. Though there have been numerous attempts in previous literature to model unsteady flow through porous media, the validity and accuracy of these attempts are not well understood, and muddied by the lack of experimental or numerical data against which they can be validated or fitted. A particularly complicated case arises for unsteady flows through high permeability media, in which there are simultaneous interactions between unsteady, viscous, and nonlinear inertial effects that remain little studied. The aim of the current work is to investigate these compounding effects by exploring the pore-scale flow fields and macroscopic relationships between the applied pressure gradient and velocity. Our objective is to establish clearer limits for the validity of the existing models of unsteady flow through porous media, and produce parametric maps for the validity of the quasi-steady assumption when porous media are subject to unsteady pressure gradients. To achieve these goals, we perform pore-scale direct numerical simulations of steady and unsteady, single-phase, Newtonian, incompressible flow through infinite periodic arrays of cylinders. Using our unsteady simulations, we perform a parametric study of the validity of both the quasi-steady Darcy equation and a popular unsteady form of the Darcy equation. The validities of these equations are explored as a function of the porosity and the driving pressure gradient amplitude and frequency. Our results show that the validity of the quasi-steady assumption decreases with increasing pressure gradient, frequency and amplitude, due to compounding effects of the unsteady and nonlinear inertial effects. Our results support the usefullness of a popular unsteady form of the Darcy equation, but show that its validity is also limited to sufficiently small frequencies and amplitudes. Using our steady simulations, we perform a comprehensive parametric study of the various macroscopic flow regimes as a function of porosity, pressure gradient, and cylinder arrangement. Using the results of over 1000 steady simulations, we develop parametric maps of the various flow regimes and the validities of popular macrscopic relationships for steady flow through porous media. Such comprehensive and detailed maps have been lacking in the literature to date, and we expect they will significantly contribute to the future development of improved macroscopic relationships using more formal upscaling methods, such as volume-averaging and homogenization.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2020 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.titleFlow through cylinder arrays subject to steady and unsteady pressure gradients
dc.typeText
dc.contributor.committeememberKee, R. J.
dc.contributor.committeememberDeCaluwe, Steven C.
dc.contributor.committeememberYin, Xiaolong
dcterms.embargo.terms2021-07-03
dcterms.embargo.expires2021-07-03
thesis.degree.nameDoctor of Philosophy (Ph.D.)
thesis.degree.levelDoctoral
thesis.degree.disciplineMechanical Engineering
thesis.degree.grantorColorado School of Mines
dc.rights.accessEmbargo Expires: 07/03/2021


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