Short-time transport properties of bidisperse suspensions and porous media: A Stokesian dynamics study

Abstract

We present a comprehensive computational study of the short-time transport properties of bidisperse hard-sphere colloidal suspensions and the corresponding porous media. Our study covers bidisperse particle size ratios up to 4 and total volume fractions up to and beyond the monodisperse hard-sphere close packing limit. The many-body hydrodynamic interactions are computed using conventional Stokesian Dynamics (SD) via a Monte-Carlo approach. We address suspension properties including the short-time translational and rotational self-diffusivities, the instantaneous sedimentation velocity, the wavenumber-dependent partial hydrodynamic functions, and the high-frequency shear and bulk viscosities and porous media properties including the permeability and the translational and rotational hindered diffusivities. We carefully compare the SD computations with existing theoretical and numerical results. For suspensions, we also explore the range of validity of various approximation schemes, notably the pairwise additive approximations with the Percus-Yevick structural input. We critically assess the strengths and weaknesses of the SD algorithm for various transport properties. For very dense systems, we discuss in detail the interplay between the hydrodynamic interactions and the structures due to the presence of a second species of a different size. C 2015 AIP Publishing LLC. [http://dx

Bidisperse and polydisperse suspension rheology at large solid fraction

“…Powell [1993, 1994a,b] used Stokesian Dynamics to calculate hydrodynamic interactions in bidisperse suspensions and showed trends which matched the general experimental observations noted above. More recently, Wang and Brady [2015] used conventional Stokesian Dynamics to study the short-time transport properties of bidisperse colloidal suspensions. In addition to rheological modifications, bidisperse suspensions in nonuniform shear such as pressure-driven flow, where particle migration occurs, are known to display segregation behavior based on particle size [Lyon and Leal [1998]; Semwogerere and Weeks [2008]], but here we will focus on conditions where the particle sizes remain well-mixed.…”

Short-time diffusion in concentrated bidisperse hard-sphere suspensions

“…The qualitative and quantitative aspects of the functions H α β (q) are extensively examined and discussed in a companion paper, 69 and here, we focus on the performance of the rescaled δγ scheme.…”

Spectral Ewald Acceleration of Stokesian Dynamics for polydisperse suspensions

“…(75) and (76) with ∆τ = 0.2, and for SEASD-nf the far-field diffusivities are from Table 1. The conventional SD result is from an efficient polydisperse implementation [11,12,83]. All the timing results are collected from a workstation with Intel i7-3770K CPU and NVIDIA GeForce GTX 680 GPU.…”

“…We present three computational examples to further validate SEASD and SEASD-nf in monodisperse and bidisperse suspensions: the short-time transport properties, the equilibrium osmotic pressure and viscoelastic moduli, and the steady shear Brownian rheology. Our validation results show that the agreement between SEASD and SEASD-nf is satisfactory over a wide range of parameters, and also provide significant insight into the dynamics of polydisperse colloidal suspensions.Presently, theoretical and computational studies on polydisperse colloidal suspensions, even for the simplest case of neutrally buoyant hard-sphere particles, are scarce, and heavily focus on the dilute or the short-time limits [8][9][10][11][12]: the former restricts HIs to the two-or three-body level, and the latter ignores suspension dynamic evolution, particularly the influence of Brownian motion. Beyond these limiting cases, we are only aware of the work of Ando & Skolnick [13], who studied particle diffusion in dense polydisperse colloidal suspensions using conventional SD in the context of biological molecular crowding.…”

“…Presently, theoretical and computational studies on polydisperse colloidal suspensions, even for the simplest case of neutrally buoyant hard-sphere particles, are scarce, and heavily focus on the dilute or the short-time limits [8][9][10][11][12]: the former restricts HIs to the two-or three-body level, and the latter ignores suspension dynamic evolution, particularly the influence of Brownian motion. Beyond these limiting cases, we are only aware of the work of Ando & Skolnick [13], who studied particle diffusion in dense polydisperse colloidal suspensions using conventional SD in the context of biological molecular crowding.…”