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Lookup NU author(s): Emeritus Professor Mike Reeks
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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.
Author(s): Zhang F, Reeks MW, Kissane M
Publication type: Article
Publication status: Published
Journal: Journal of Aerosol Science
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
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