Hydrodynamic theory of wet particle systems

Sudeshna Roy

    Research output: ThesisPhD Thesis - Research UT, graduation UT

    165 Downloads (Pure)

    Abstract

    External forces lead to granular flow under the condition that the applied shear stress reaches the yield (shear) stress while another stress must be maintained for continuous flow in steady state. Most studies in granular physics focus on dry granular materials and their flow rheology. However, wet granular materials are ubiquitous in geology and many real world applications where interstitial liquid is present between the grains. There are several proposals for flow rules of dry and wet granular materials available in the literature. These flow rules differ in complexity and in the number of parameters, which are combined in the equations. The main focus areas of my research are (i) the formulation of suitable constitutive equations for the hydrodynamic density-stress-strain relations, specifically for wet granular materials, (ii) the deduction of the constitutive equations from discrete element simulations, and (iii) the validation of the micro-macro transition with numerical, theoretical and experimental results. The geometrical set-up of split-bottom shear cell used in my research is most appropriate for assessing the shear band originating from the split position that widens near the free surface.
    My research proposes a modified generalized flow rule/rheology to close the fundamental conservation laws for mass and momentum. Subsequently, a correlation is developed between the micro parameters and the {steady state cohesion in the limit} of very low confining pressure. Another aspect of studying unsaturated granular media is the movement of interstitial liquid due to the rupture of existing and formation of new liquid bridges. Shearing a wet granular system causes a re-distribution and transport of the interstitial liquid. The liquid transport can be modeled by a diffusion equation with a space-dependent diffusive coefficient in the split bottom geometry. Alternatively, it is shown here that this is an advective-diffusive process with constant diffusivity coefficient and a space-dependent drift, when transformed to an appropriate set of variables that can be solved analytically. The final chapter of this thesis concerns the experimental work exploring the surface flow profile for different dry and wet granular materials.
    Original languageEnglish
    Awarding Institution
    • University of Twente
    Supervisors/Advisors
    • Luding, Stefan , Supervisor
    • Weinhart, Thomas , Supervisor
    Thesis sponsors
    Award date26 Jan 2018
    Place of PublicationEnschede
    Publisher
    Print ISBNs978-90-365-4468-9
    DOIs
    Publication statusPublished - 26 Jan 2018

    Fingerprint

    granular materials
    hydrodynamics
    interstitials
    constitutive equations
    liquids
    rheology
    shear stress
    shear
    liquid bridges
    deduction
    theses
    cohesion
    coefficients
    geology
    conservation laws
    shearing
    confining
    diffusivity
    proposals
    momentum

    Cite this

    Roy, Sudeshna . / Hydrodynamic theory of wet particle systems. Enschede : University of Twente, 2018. 136 p.
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    title = "Hydrodynamic theory of wet particle systems",
    abstract = "External forces lead to granular flow under the condition that the applied shear stress reaches the yield (shear) stress while another stress must be maintained for continuous flow in steady state. Most studies in granular physics focus on dry granular materials and their flow rheology. However, wet granular materials are ubiquitous in geology and many real world applications where interstitial liquid is present between the grains. There are several proposals for flow rules of dry and wet granular materials available in the literature. These flow rules differ in complexity and in the number of parameters, which are combined in the equations. The main focus areas of my research are (i) the formulation of suitable constitutive equations for the hydrodynamic density-stress-strain relations, specifically for wet granular materials, (ii) the deduction of the constitutive equations from discrete element simulations, and (iii) the validation of the micro-macro transition with numerical, theoretical and experimental results. The geometrical set-up of split-bottom shear cell used in my research is most appropriate for assessing the shear band originating from the split position that widens near the free surface.My research proposes a modified generalized flow rule/rheology to close the fundamental conservation laws for mass and momentum. Subsequently, a correlation is developed between the micro parameters and the {steady state cohesion in the limit} of very low confining pressure. Another aspect of studying unsaturated granular media is the movement of interstitial liquid due to the rupture of existing and formation of new liquid bridges. Shearing a wet granular system causes a re-distribution and transport of the interstitial liquid. The liquid transport can be modeled by a diffusion equation with a space-dependent diffusive coefficient in the split bottom geometry. Alternatively, it is shown here that this is an advective-diffusive process with constant diffusivity coefficient and a space-dependent drift, when transformed to an appropriate set of variables that can be solved analytically. The final chapter of this thesis concerns the experimental work exploring the surface flow profile for different dry and wet granular materials.",
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    language = "English",
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    Hydrodynamic theory of wet particle systems. / Roy, Sudeshna .

    Enschede : University of Twente, 2018. 136 p.

    Research output: ThesisPhD Thesis - Research UT, graduation UT

    TY - THES

    T1 - Hydrodynamic theory of wet particle systems

    AU - Roy, Sudeshna

    PY - 2018/1/26

    Y1 - 2018/1/26

    N2 - External forces lead to granular flow under the condition that the applied shear stress reaches the yield (shear) stress while another stress must be maintained for continuous flow in steady state. Most studies in granular physics focus on dry granular materials and their flow rheology. However, wet granular materials are ubiquitous in geology and many real world applications where interstitial liquid is present between the grains. There are several proposals for flow rules of dry and wet granular materials available in the literature. These flow rules differ in complexity and in the number of parameters, which are combined in the equations. The main focus areas of my research are (i) the formulation of suitable constitutive equations for the hydrodynamic density-stress-strain relations, specifically for wet granular materials, (ii) the deduction of the constitutive equations from discrete element simulations, and (iii) the validation of the micro-macro transition with numerical, theoretical and experimental results. The geometrical set-up of split-bottom shear cell used in my research is most appropriate for assessing the shear band originating from the split position that widens near the free surface.My research proposes a modified generalized flow rule/rheology to close the fundamental conservation laws for mass and momentum. Subsequently, a correlation is developed between the micro parameters and the {steady state cohesion in the limit} of very low confining pressure. Another aspect of studying unsaturated granular media is the movement of interstitial liquid due to the rupture of existing and formation of new liquid bridges. Shearing a wet granular system causes a re-distribution and transport of the interstitial liquid. The liquid transport can be modeled by a diffusion equation with a space-dependent diffusive coefficient in the split bottom geometry. Alternatively, it is shown here that this is an advective-diffusive process with constant diffusivity coefficient and a space-dependent drift, when transformed to an appropriate set of variables that can be solved analytically. The final chapter of this thesis concerns the experimental work exploring the surface flow profile for different dry and wet granular materials.

    AB - External forces lead to granular flow under the condition that the applied shear stress reaches the yield (shear) stress while another stress must be maintained for continuous flow in steady state. Most studies in granular physics focus on dry granular materials and their flow rheology. However, wet granular materials are ubiquitous in geology and many real world applications where interstitial liquid is present between the grains. There are several proposals for flow rules of dry and wet granular materials available in the literature. These flow rules differ in complexity and in the number of parameters, which are combined in the equations. The main focus areas of my research are (i) the formulation of suitable constitutive equations for the hydrodynamic density-stress-strain relations, specifically for wet granular materials, (ii) the deduction of the constitutive equations from discrete element simulations, and (iii) the validation of the micro-macro transition with numerical, theoretical and experimental results. The geometrical set-up of split-bottom shear cell used in my research is most appropriate for assessing the shear band originating from the split position that widens near the free surface.My research proposes a modified generalized flow rule/rheology to close the fundamental conservation laws for mass and momentum. Subsequently, a correlation is developed between the micro parameters and the {steady state cohesion in the limit} of very low confining pressure. Another aspect of studying unsaturated granular media is the movement of interstitial liquid due to the rupture of existing and formation of new liquid bridges. Shearing a wet granular system causes a re-distribution and transport of the interstitial liquid. The liquid transport can be modeled by a diffusion equation with a space-dependent diffusive coefficient in the split bottom geometry. Alternatively, it is shown here that this is an advective-diffusive process with constant diffusivity coefficient and a space-dependent drift, when transformed to an appropriate set of variables that can be solved analytically. The final chapter of this thesis concerns the experimental work exploring the surface flow profile for different dry and wet granular materials.

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    DO - 10.3990/1.9789036544689

    M3 - PhD Thesis - Research UT, graduation UT

    SN - 978-90-365-4468-9

    PB - University of Twente

    CY - Enschede

    ER -