Assessment of hindered diffusion in arbitrary geometries using a multiphase DNS framework
Journal article, 2021

The hydrodynamics around a Brownian particle has a noticeable impact on its hindered diffusion in arbitrary geometries (such as channels/pores) due to reduced mobility close to walls. These effects are difficult to describe at sub-pore scales, wherein a complete analytical solution of the underlying hydrodynamics is challenging to obtain. Here, we propose a coupled Langevin-multiphase direct numerical simulation (DNS) framework, that fully resolves the hydrodynamics in such systems and consequently provides an on-the-fly capability to probe local instantaneous particle diffusivities.

We validate and establish the capabilities of this framework in square micro-channels (under varying degrees of hydrodynamic confinement) and in an arbitrary pore. Our results show that directional variations in mean-squared displacements, velocity auto-correlation functions and diffusivities of the Brownian particle, due to inherent asymmetries in the geometry are adequately captured. Further, a local anisotropy in the hydrodynamic resistances along the co-axial direction of the channel is also noted.

Micro-channel and Mobility

Immersed boundary method

Hydrodynamic resistance

CFD

Brownian diffusion

Hindered diffusion

Author

Ananda Subramani Kannan

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Andreas Mark

Fraunhofer-Chalmers Centre

Dario Maggiolo

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Gaetano Sardina

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Srdjan Sasic

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Henrik Ström

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Chemical Engineering Sciences

0009-2509 (ISSN)

Vol. 230 116074

A continuum model for Brownian motion in rarefied gas-solid flows

Swedish Research Council (VR), 2016-01-01 -- 2019-12-31.

Areas of Advance

Transport

Production

Energy

Subject Categories

Pharmaceutical Sciences

Energy Engineering

Fluid Mechanics and Acoustics

Infrastructure

C3SE (Chalmers Centre for Computational Science and Engineering)

DOI

10.1016/j.ces.2020.116074

More information

Latest update

1/11/2021