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Particle resuspension in turbulent boundary layers and the influence of non-Gaussian removal forces

Lookup NU author(s): Emeritus Professor Mike Reeks

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Abstract

The work described is concerned with the way micron-size particles attached to a surface are resuspended when exposed to a turbulent flow. An improved version of the Rock’n’Roll model (Reeks & Hall, 2001) is developed where this model employs a stochastic approach to resuspension involving the rocking and rolling of a particle about surface asperities arising from the moments of the fluctuating drag forces acting on the particle close to the surface. In this work, the model is improved by using values of both the streamwise fluid velocity and acceleration close to the wall obtained from Direct Numerical Simulation (DNS) of turbulent channel flow. Using analysis and numerical calculations of the drag force on a sphere near a wall in shear flow (O’Neill, 1968; Lee & Balachandar, 2010) these values are used to obtain the joint distribution of the moments of the fluctuating drag force f(t) and its rate of hange acting on a particle attached to a urface. In so doing the influence of highly non-Gaussian forces (associated with the weeping and ejection events in a turbulent boundary layer) on short and long term esuspension rates is examined for a sparse monolayer coverage of particles, along with the dependence of the resuspension upon the timescale of the particle motion attached to the surface, the ratio of the rms/mean of the removal force and the distribution of adhesive forces. Model predictions of the fraction resuspended are compared with experimental results.


Publication metadata

Author(s): Zhang F, Reeks MW, Kissane M

Publication type: Article

Publication status: Published

Journal: Journal of Aerosol Science

Year: 2013

Volume: 58

Pages: 103-128

Print publication date: 01/04/2013

Online publication date: 01/12/2012

Acceptance date: 14/11/2012

Date deposited: 06/05/2013

ISSN (print): 0021-8502

ISSN (electronic): 1879-1964

Publisher: Elesevier Ltd

URL: http://dx.doi.org/10.1016/j.jaerosci.2012.11.009

DOI: 10.1016/j.jaerosci.2012.11.009


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