Bulletin of the American Physical Society
APS March Meeting 2021
Volume 66, Number 1
Monday–Friday, March 15–19, 2021; Virtual; Time Zone: Central Daylight Time, USA
Session E24: Granular, Porous Media, and Multiphase Flows ILive
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Sponsoring Units: DFD Chair: Nathan Keim, Pennsylvania State University |
Tuesday, March 16, 2021 8:00AM - 8:12AM Live |
E24.00001: Scaling laws for intrusion into granular materials and granular-fluid mixtures Abe Clark, Joshua Dijksman, Nasser F Krizou, Marc Brassard, Neil Causley, Joshua Strader This talk will summarize our recent work on moderate- and high-speed impacts into (1) dry granular media, (2) dense suspensions and (3) fluid-saturated granular beds. We show experimental, computational, and theoretical results that, for all three material types, reveal important insights regarding the underlying material response. In particular, we focus on the initial stages of impact, and we study how the peak forces and time scales depend on properties of the intruder (e.g., speed, size, mass, and shape) and of the material (e.g., grain size, grain packing fraction, grain stiffness, grain packing fraction, and fluid viscosity). For (1), we find that the peak forces are set by elastic response according to power-law scaling forms which are inconsistent with Poncelet and shock models; for (2), we find that the ubiquitous added-mass model fails to capture several crucial features of the dynamics, likely due to the neglect of large, viscous-like forces; and, for (3), we test and generally confirm Darcy-Reynolds theory, although we observe important discrepancies for high-viscosity fluids. |
Tuesday, March 16, 2021 8:12AM - 8:24AM Live |
E24.00002: Using colloidal deposition to mobilize immiscible fluids from porous media Joanna Schneider, Rodney Priestley, Sujit Datta Colloidal particles hold promise for mobilizing trapped immiscible fluids from porous media, with implications for key water applications. Most studies focus on accomplishing this goal using particles that localize at immiscible fluid interfaces. Researchers typically seek to optimize the surface activity of particles while minimizing their deposition onto the surrounding solid matrix. Here, we demonstrate that deposition can, surprisingly, promote mobilization of a trapped fluid from a porous medium. Using confocal microscopy, we directly visualize colloidal particles and trapped immiscible fluid within a transparent, 3D porous medium. As particles deposit on the solid matrix, more trapped fluid become mobilized. We unravel the underlying physics by analyzing the extent of deposition and the geometry of trapped fluid droplets at the pore scale: deposition increases viscous stresses on droplets, overcoming the influence of capillarity that keeps them trapped. This analysis enables us to predict the extent of fluid mobilized through colloidal deposition and reveals a new way by which colloids can be harnessed to mobilize trapped fluid from a porous medium. |
Tuesday, March 16, 2021 8:24AM - 8:36AM Live |
E24.00003: Forced Imbibition in Stratified Porous Media Nancy Lu, Amir Pahlavan, Christopher Browne, Daniel Amchin, Howard A Stone, Sujit Datta Imbibition plays a central role in diverse energy, environmental, and industrial processes. In many cases, the medium has multiple parallel strata of different permeabilities; however, how this stratification impacts imbibition is poorly understood. We address this gap in knowledge by directly visualizing forced imbibition in three-dimensional (3D) porous media with two parallel strata. We find that imbibition is spatially heterogeneous: for small capillary number Ca, the wetting fluid preferentially invades the fine stratum, while for Ca above a threshold value, the fluid instead preferentially invades the coarse stratum. This threshold value depends on the medium geometry, the fluid properties, and the presence of residual wetting films in the pore space. These findings are well described by a linear stability analysis that incorporates crossflow between the strata. Thus, our work provides quantitative guidelines for predicting and controlling flow in stratified porous media. |
Tuesday, March 16, 2021 8:36AM - 8:48AM Live |
E24.00004: Mapping out the force network in shear thickening colloidal suspensions Meera Ramaswamy, Itay Griniasty, Itai Cohen When dense colloidal suspensions are sheared, the viscosity can increase by over an order of magnitude as illustrated by the many videos of people running on cornstarch-water mixtures. While there are many studies on both the macroscopic changes in the viscosity and the microscopic suspension properties that cause these bulk changes, little is known about the mesoscale – how the forces in these systems are transmitted and the force network that is set up in these suspensions. Here, we present a novel shear protocol that allows us to gain insight into the three dimensional force network in these shear thickening suspensions. We find a highly anisotropic stress distribution that depends on the applied shear rate, and the volume fraction. We compare the results of these experiments to those from a recently proposed tensorial model for shear thickening. These results are key to further understanding and tuning the behavior of shear thickening suspensions. Moreover, this protocol can be generalized to probe the different stress components in a variety of other systems. |
Tuesday, March 16, 2021 8:48AM - 9:00AM Live |
E24.00005: Gas-liquid phase separation in a soft porous medium Oliver Paulin, Liam Morrow, Matthew Hennessy, Christopher W. MacMinn Various biological and chemical processes can lead to the nucleation and growth of gas bubbles within the pore space of an otherwise liquid-saturated granular medium, such as in lake beds and waste ponds. The gas is typically non-wetting and, as the bubbles approach the pore size, it is energetically costly for them to invade narrow pore throats. If the solid skeleton is sufficiently soft, it is favourable for the bubbles to displace the solid grains and form macroscopic cavities. Here, we consider this process through the lens of phase separation, where thermomechanics govern the separation of a gas phase from a gas-liquid-solid mixture. We construct a phase-field model informed by large-deformation poromechanics, in which two immiscible fluids interact with a poroelastic solid skeleton. Our model captures the competing effects of elasticity and gas-liquid-solid interactions. As a model problem, we consider an initial distribution of gas in the pore space that separates into multiple gas cavities, which then coarsen over time as the smaller cavities collapse and the larger cavities expand. We identify the key parameters that control phase separation, the conditions that favour the formation of gas cavities, and the characteristic size of the resulting gas cavities. |
Tuesday, March 16, 2021 9:00AM - 9:12AM Live |
E24.00006: Computational characterization of nonwoven fiber materials: Predicting permeability from pore-space morphology Fang Wang, Suman Kumari, Ulf Schiller Nonwoven fibrous membranes are widely used as filtration media, and tailoring the microstructure of the pore space is a key to improving filtration efficiency. In this contribution, we present a computational framework for generating realistic random fibrous media with a wide range of porosities and systematically analyze the effect of pore size distribution on permeability and tortuosity. Combining the pore-network statistical analysis with pore-scale flow simulations reveals the influence of the statistical pore size distribution on the effective fluid transport properties over a wide range of macroscopic porosities. The computational framework is applicable to segmentation of experimental imaging techniques such as X-ray computed tomography or scanning electron microscopy and thus enables rapid characterization and design of porous media with tailored properties for filtration and separation applications. |
Tuesday, March 16, 2021 9:12AM - 9:24AM Live |
E24.00007: Transport and filtration of aggregate particles in a porous media Nolwenn Delouche, Hervé Tabuteau The transport of colloidal suspensions in confined environments like the pores of filters and soils often leads to the formation of partial or complete clogging. Depending on the particle size D and the channel width W, the pore is blocked by sieving a large particle, by formation of an arch or by progressive accumulation. However, even though the suspension used to determine the type of clogging are rather monodisperse, it turns out that aggregates present in minute quantities are mainly responsible of the clog formation, their rotation dynamics near the pore surface enhancing their deposition compared to spherical particles. Here, we study the impact of these aggregates on the clogging of interconnected pores within a porous medium. We develop an in-situ particle characterization and a clog detection which enable us determining both the type of particles that are captured and the temporal clogging dynamics of adjacent pores. We show that aggregates are mainly captured near the pore entrance and their deposition are enhances by the pore cross talk. These conclusions underline the importance of particle composition and concentration of the suspensions to filter. It also opens up interesting perspectives in the design of new filters in which pore clogging is delayed. |
Tuesday, March 16, 2021 9:24AM - 9:36AM Live |
E24.00008: Percolation through Voids around Structurally Disordered Impermeable Inclusions Donald Priour The permeability of porous media with respect to fluid flow is contingent on the availability of channels comprised of connected voids among the particles making up the medium. If the density of the latter exceeds a critical value, known as the percolation threshold, fluid flow on macroscopic scales is blocked. To account for the high degree of irregularity of grains in realistic systems, we provide a geometrically exact treatment of percolation phenomena involving strongly disordered barrier particles. On the one hand, we randomly perturb the shapes of grains (e.g. for cubes, tetrahedra, and icosahedra), with an insensitivity of the critical volume fraction to weak disorder giving way to a monotonic rise for moderate to strong structural distortions. On the other hand, to examine assemblies formed from grains created by agressive fragmentation processes, we examine both aligned and randomly oriented cubes fragmented by randomly placed slicing planes with isotropically sampled orientations. For both the former and the latter, we find a convergence of percolation thresholds to a common critical void volume fraction for a mean number of sustained stochastically chosen slices on the order of 10. We also discuss the effect of weathering on the critical grain concentration. |
Tuesday, March 16, 2021 9:36AM - 9:48AM Live |
E24.00009: Nanoparticle transport in porous media Shima Parsa, Tony Wong Nanoparticle dispersion in soil is a concerning source of soil and water contamination. The transport of nanoparticles in porous media is determined by the balance of advective, diffusive and electrostatic forces. We investigate the two-way coupling between retention of nanoparticles and pore-level flow distribution experimentally. We show that retention of nanoparticles results in development of no flow zones and diversion of flow into new direction. This results in enhanced distribution of nanoparticles across the medium. |
Tuesday, March 16, 2021 9:48AM - 10:00AM Live |
E24.00010: Deformation-driven solute transport in soft porous media Matilde Fiori, Satyajit Pramanik, Christopher W. MacMinn Solute transport plays an important role in many soft porous materials, including the movement of contaminants in soils and the movement of nutrients and waste in living tissues and tissue-engineering scaffolds. These systems are also often exposed to large, periodic loading and deformation, which drives nontrivial fluid motion and changes in pore structure. Here, we study the strong coupling between fluid flow and mechanical stimulation during periodic deformations using a 1D continuum model based on large-deformation poroelasticity. We show that these reversible deformations lead to non-reversible spreading and mixing, even in a homogeneous medium. We analyse the three primary mechanisms of solute transport (advection, molecular diffusion, and mechanical dispersion) and study their separate impacts on the solute distribution. We also identify the key dimensionless parameters that govern deformation-driven transport, and we study their qualitative and quantitative impacts on solute spreading and mixing. |
Tuesday, March 16, 2021 10:00AM - 10:12AM Live |
E24.00011: A phase-field model for capillary bulldozing Liam Morrow, Oliver Paulin, Matthew Hennessy, Christopher W. MacMinn
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Tuesday, March 16, 2021 10:12AM - 10:24AM Live |
E24.00012: Capillary replacement between two mutually immiscible liquids on an open channel Hiroki Yasuga, Ko Okumura Capillarity-driven microfluidic devices have been receiving considerable attention in engineering and medical applications. Although paper is a well-known material as a capillary pump for pregnancy tests, microgrooves or repetitive microstructure patterns are intensively studied equally well for capillary pumps [1]. Almost all previous capillarity-driven microfluidic devices involve spontaneous flow of a single liquid. Recently, fundamental aspects of the spontaneous replacement between two mutually immiscible liquids have been clarified [2]. However, the physical understanding of the replacement is still premature for microfluidic implementation. In this study, we investigated the capillary replacement on an open channel. In particular, we focused on the spontaneous replacement of a pre-filled aqueous solution with an oil more wettable on the channel surface in an open channel. |
Tuesday, March 16, 2021 10:24AM - 10:36AM Live |
E24.00013: Simulating fluid flow with carbon dioxide in digital rock Mathias Steiner, Rodrigo Ferreira, Ronaldo Giro Mitigating climate change which is driven by carbon dioxide release into the atmosphere requires scientific advancements in the area of carbon dioxide capture, conversion and storage. We report progress in our research of fluid flow scenarios in geological samples that involve carbon dioxide injection at pore scale. Specifically, we generate capillary network representations by extracting the geometric boundaries of the connected pore space from x-ray microscale computer tomography data of porous reservoir rock samples. We present our initial results of capillary network flow simulations obtained with hierarchical, multi-phase flow models which are calibrated through molecular dynamics simulation. The methods developed here are more broadly applicable for studying problems of fluid flow in porous media and their application will benefit the understanding and improvement of carbon dioxide conversion and storage. |
Tuesday, March 16, 2021 10:36AM - 10:48AM Live |
E24.00014: Displacement flow in an Elastic Fracture Sri Savya Tanikella, Emilie Dressaire We revisit the classical displacement flow problem in a growing fracture. We report an experimental study of water injection in an oil-filled fracture in an elastic brittle matrix. The initial oil-filled crack is penny-shaped, and its growth dynamics is controlled by the stress intensity factor, in what is known as the toughness regime of propagation. Upon injection of water, the crack further expands. We investigate the propagation of the fracture and the displacement of the oil/water interface. Our experiments show that the propagation dynamics in this displacement configuration differs from the single-fluid injection. Scaling arguments are provided to explain the experimental results and provide insights into the underlying physics. |
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