Short-time dynamics of permeable particles in concentrated suspensions

Abstract

First-order virial expansion of short-time diffusion and sedimentation coefficients of permeable particles suspensions Phys. Fluids 23, 083303 (2011); 10.1063/1.3626196 Rotational and translational self-diffusion in concentrated suspensions of permeable particles 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.

Hydrodynamic radius approximation for spherical particles suspended in a viscous fluid: Influence of particle internal structure and boundary

“…It has been checked that for a wide range of particle internal structures and boundaries, and the no-overlap direct interactions, deviations from the above approximation are very small [29,31,32,34] and as such, hard to be detected in experiments, even for relatively dense suspensions.…”

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

“…7. For monodisperse suspensions, U s /U 0 from Ladd 81 and Abade et al 91 are also shown in Fig. 7(a) for comparison.…”

High-frequency viscosity of concentrated porous particles suspensions

“…We have calculated to high precision both k H (from the series expansion of J(r) in inverse powers of r) and η ∞ (using a hydrodynamic multipole method corrected for lubrication [39][40][41][42], encoded in our hydromultipole program package extended to porous spheres [43,44]). The hydrodynamic structure of the particles enters into the hydromultipole code through a single-particle friction operator only, whose form is known for a variety of particle models with different internal hydrodynamic structures [39,52].…”

“…The many-sphere hydrodynamic interactions in a concentrated system of porous spheres are fully accounted for by our precise hydrodynamic multipole method (see [39][40][41][42] for details) encoded in the hydromultipole program which we have extended by the inclusion of particle porosity [43,44]. Using this method, we have obtained data for η ∞ for volume fractions φ covering the equilibrium fluid phase regime.…”