Near-wall dynamics of inertial particles in dilute turbulent channel flows

Abstract

This is a repository copy of Near-wall dynamics of inertial particles in dilute turbulent channel flows.

Agglomeration dynamics in liquid–solid particle-laden turbulent channel flows using an energy-based deterministic approach

“…The Newtonian acceleration and velocity differential equations are derived by considering the force-balance between the particle's inertia and the fluid (Maxey, 1987;Riley and Patterson Jr, 1974). Within this study, we consider a calcite-water system wherein the density ratio is low ( = 2.71) and, as such, contributions from forces other than drag are likely to be relevant, as observed previously (Homann and Bec, 2010;Mortimer et al, 2019). For this reason, we have chosen to consider contributions from all hydrodynamic forces (drag, lift, virtual mass and pressure gradient).…”

“…For this reason, we have chosen to consider contributions from all hydrodynamic forces (drag, lift, virtual mass and pressure gradient). The relevance of all these forces based upon channel wall-distance can be found in Mortimer et al (2019). The Basset history force has been neglected due to long computation times and previous evidence demonstrating little effect on the resulting particle motion (Fairweather and Hurn, 2008;Daitche, 2015).…”

“…(4) and (5), represents the particle position vector, is the particle velocity vector, is the fluid velocity vector at the position of the particle, = is the slip velocity between the fluid and the particle, is the particle diameter non-dimensionalised by the channel half-height, is the density ratio between the fluid and the particle and is the vorticity of the fluid at the particle position, given by = × . Further details surrounding the calculation and origin of these terms are provided in Mortimer et al (2019).…”

“…7 presents the mean streamwise particle velocity profiles for all cases. Due to a lack of validation data or alternative predictions for the particle properties employed, we do not include here any validation for the particulate phase results, however an alternative validation can be found in Mortimer et al (2019) which utilizes the same LPT solver. As expected, the particles exhibit very similar macroscopic behaviour to that of the fluid phase, since their Stokes numbers are low and they have little or no difficulty adjusting to the local fluid velocity.…”

“…Turbophoresis refers to the tendency for particles to migrate toward regions of low turbulence kinetic energy, again observed to magnitudinally scale with Stokes number (Kuerten and Vreman, 2005;Marchioli et al, 2008;Marchioli and Soldati, 2002). Upon reaching the wall regions, particles interact with local turbulence structures and show a wide variety of behaviours based on their inertial properties (Mortimer et al, 2019).…”