Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session Y27: Granular Porous Media and Multiphase Flows IIRecordings Available
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Sponsoring Units: DFD Chair: Larry Galoway, University of Pennsylvania Room: McCormick Place W-187C |
Friday, March 18, 2022 8:00AM - 8:12AM |
Y27.00001: Delamination and poroelastic deformation in drying colloidal suspension drops Paul Lilin, Irmgard Bischofberger The drying of sessile drops of colloidal suspensions leads to the formation of fracture patterns. As water evaporates, a solidification front propagates from the edge of the drop, leaving behind a thin close-packed particle deposit. For drops of initial particle volume fraction beyond 5%, this solid deposit eventually covers the entire wetted area. Water evaporation from the deposit and adhesion to the substrate lead to the formation of regular radial cracks which define the 'petals' of a flower-like crack pattern. The deposit then progressively delaminates from the substrate and the petals bend upward. This deformation had been linked to a poroelastic bending moment created by the vertical flow of water in the drying deposit. However, by monitoring the complete shape of the petals, we show that the petal curvature remains constant except close to the moving delamination front, despite vertical flows occurring through the entire deposit. Furthermore, measuring the bending characteristics for a range of deposit thicknesses and evaporation rates, we find a scaling law distinct from that expected from the bending moment theory. These findings point towards plastic deformation caused by the mean pore pressure in the deposit as the origin of the bending. |
Friday, March 18, 2022 8:12AM - 8:24AM |
Y27.00002: Dust Dispersion by Shock Waves: An Eulerian-Lagrangian Study Akhil V. Marayikkottu, Deborah A Levin A clear understanding of the mechanism of dust lifting from the ground is necessary to study dust dispersion in explosions and other industrial processes. The mechanism of dust dispersion is affected by various parameters such as the shock strength, the curvature of shock bending near the particle surface, and the vortices or flow disturbances generated in the vicinity of the bed through back coupling. High-fidelity simulations can provide a clearer understanding of the primary contributors to dust dispersion. In this talk, we investigate the general phenomenology of dust dispersion behind a traveling shock wave using the Eulerian-Lagrangian modules appended to the compressible FLASH solver. The study will address gas-particle, particle-gas, and particle-particle interactions critical in the complex multiphase system through surrogate models to estimate the relative importance of these interactions. |
Friday, March 18, 2022 8:24AM - 8:36AM |
Y27.00003: Changing the flow profile and resulting drying pattern of dispersion droplets via contact angle modification Carmen Morcillo Perez, Job Thijssen, Marcel Rey, Benjamin D Goddard The evaporation of suspension droplets is a complex physical process, and prediction and control over particle deposit patterns obtained from sessile droplet evaporation are essential for many industrial processes such as ink-jet printingĀ or crop-care applications. We present a systematic investigation of the effect of surface wettability on the evaporation dynamics of a particle-laden droplet, including the contact line stick-slip, hydrodynamic flow of the particles and deposit after evaporation. We tuned the wettability of glass slides using silanisation; and measured the flow inside the drying droplets using fluorescent tracer particles. We found that the internal flows shift from predominantly outward flow for low contact angles to predominantly inward flow for large contact angles. Additionally, upon increasing the substrates hydrophobicity, the dried deposit gradually changes from the typical coffee-ring to a central stain. Last, we corroborate these experimental findings with dynamic density functional theory, modelling the droplet evaporation process and stick-slip behaviour of the contact line. Our investigation suggests that the wettability of the substrate can substantially alter hydrodynamic flow within drying droplets and therefore the resulting particle deposit. |
Friday, March 18, 2022 8:36AM - 8:48AM |
Y27.00004: Strain Driven Ordering of Nanoparticles in a Dense Silica Colloid Xiao-Min Lin, Hongrui He, Qiming He, Jelena Dinic, Wei Chen, Zhang Jiang, Suresh Narayanan
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Friday, March 18, 2022 8:48AM - 9:00AM |
Y27.00005: Role of shear induced migration on the development and stability of a particle-laden falling film Darish Jeswin Dhas Sam, Anubhab Roy We study the role of shear induced migration and particle induced normal stresses on the boundary layer formation and stability of a particle-laden, gravity-driven shallow flow. Looking at the boundary layer formation at the `shallow' limit, we find that increasing bulk particle volume fractions lead to a reduction in the entrance length. In the absence of particles, gravity-driven shallow flows are known to exhibit a long-wavelength instability, as first identified by Yih (1963), and a short wave instability, as identified by Kelley (1989). We perform a linear stability analysis and find that the shear-induced migration of particles leads to an enhancement of both modes of instability. We also find that this prediction of an enhanced instability is independent of the choice constitutive model used to describe the particle phase as long as the chosen model has elements of shear induced migration. |
Friday, March 18, 2022 9:00AM - 9:12AM |
Y27.00006: Transport phenomena of smectic defects through arrays of micropillars Tyler N Shendruk, Jack Paget, Marco G Mazza, Andrew J Archer From industrial processes to living systems, simulations and analysis of liquid crystals and their defects reveal fascinating insights into transport processes in these complex liquids. Continuum modelling of liquid-crystal systems is essential to understanding transport in large systems, involving complex geometries. In this study, we use a recently developed complex order parameter tensor to simultaneously describe the local degree of smectic ordering, the orientation of the layers, and local compression. Through minimization of a Landau free energy, we present a range of defect structures in frustrated, confined geometries. By extending our model to simulate the hydrodynamics of smectics, we explore flows through micropillar arrays. We quantify how the competition between material and geometric length scales governs defect dynamics and consequently bulk transport. Our results suggest design principles for engineering microfluidic systems, which can enable or hinder permeation of smectic mesophases, and highlight the strengths of our complex tensorial formalism to enable more comprehensive studies of flowing smectic liquid crystals. |
Friday, March 18, 2022 9:12AM - 9:24AM |
Y27.00007: Dispersive effects in constituent transport during multiphase flows through porous media Prabir Daripa, Sourav Dutta In Daripa-JCP-2017 and Daripa-ANM-2019, we developed a mathematical model and a numerical method to simulate chemical-enhanced oil recovery using polymer-surfactant flooding. In this work, we study the effect of anisotropic mechanical dispersion and molecular diffusion on the advective transport of passive constituents like polymer. Also, we numerically investigate the effect of potentially nonlinear interactions between dispersive transport, capillary effects, and multiscale heterogeneity, on a model immiscible, two-phase flow problem through porous media.Numerical results demonstrating the effect of dispersion on viscous fingering in two-phase flow and on the efficiency of polymer-enhanced oil recovery will be presented. |
Friday, March 18, 2022 9:24AM - 9:36AM Withdrawn |
Y27.00008: Approximate analytic solution of potential flow around a rectangle Ildoo Kim It is critically important to find a right scale to solve problems in fluid mechanics. However, it is sometimes obscure to define a correct measure for a given system. For example, in study of wake behind a circular object or behind a rectangular object, the Reynolds number of two cases cannot be compared uniformly, because the definitions of 'the characteristic length scale' are different for two cases. The comparison between two cases may possible only if Reynolds numbers are defined in the same context in two cases. The starting point of this study is to assume that the length scales of flows can be set up by surrounding length scale of potential flow. For quantitative evaluation of such length scales, it is critically important to solve for the potential flow around a rectangle, whose exact solution is not available. Instead, we solve for approximate and analytic solution by the discretization and the optimization using multiple linear regression. |
Friday, March 18, 2022 9:36AM - 9:48AM |
Y27.00009: Time efficient pattern simulation in multiport Hele-Shaw cells using Voronoi tessellations Siddharth Tiwary, Rohit Rushil, Sachin D Kanhurkar, Rupesh Shingte, Nihal Tilekar, Amitabh Bhattacharya, Prasanna Gandhi Controlled fabrication of families of array patterns has been reported in the recent past using spatially varying port locations in multiport Hele-Shaw cells (MPHSC). Numerical simulations of this phenomenon are computationally expensive, requiring the solution of a time-dependent Poisson's equation with temporally varying boundary conditions. In this paper, we propose simulations of crystal-growth Voronoi tessellations to obtain, within engineering accuracy, the final patterns formed in MPHSC and to enable further interesting investigations. Specifically, we investigate situations with large numbers of ports, and situations where ports on a fixed lattice are digitally controlled both in time and space. The fast marching algorithm employed here substantially reduces the time required for simulation. Our predictions are compared to the CFD results and experimental results to demonstrate efficacy and assess conditions under which the proposed crystal-growth Voronoi diagrams model the final state well. |
Friday, March 18, 2022 9:48AM - 10:00AM |
Y27.00010: Ion transport within Janus nanopores: Molecular Dynamics vs Continuum Johnson Dhanasekaran, Joan M Montes de Oca, Juan De Pablo Predictions of continuum theory are compared against extensive molecular dynamics simulations of a nanoscale Janus membrane performed with explicit ions and water molecules. The ‘Janus pore’ used here consists of three regions, each with a different diameter and charge, and application of a potential difference leads to complex arrangement of ions and non-trivial transport along the channel. These details are critical to the design and development of new power generation devices, such as the Janus membrane. We test ion distributions, solvent velocities, and electric current and report the agreement as well as important differences between the full atomistic and continuum calculation, of ions embedded in a dielectric continuum and driven by the coupling of Poisson electrostatics, Nernst-Planck transport, and Navier-Stokes hydrodynamics. |
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