Campus Units

Chemical and Biological Engineering

Document Type

Article

Research Focus Area

Computational Fluid Dynamics

Publication Version

Accepted Manuscript

Publication Date

3-10-2019

Journal or Book Title

Journal of Fluid Mechanics

Volume

862

First Page

449

Last Page

489

DOI

10.1017/jfm.2018.895

Abstract

Inertial particles in turbulent flows are characterised by preferential concentration and segregation and, at sufficient mass loading, dense particle clusters may spontaneously arise due to momentum coupling between the phases. These clusters, in turn, can generate and sustain turbulence in the fluid phase, which we refer to as cluster-induced turbulence (CIT). In the present work, we tackle the problem of developing a framework for the stochastic modelling of moderately dense particle-laden flows, based on a Lagrangian probability-density-function formalism. This framework includes the Eulerian approach, and hence can be useful also for the development of two-fluid models. A rigorous formalism and a general model have been put forward focusing, in particular, on the two ingredients that are key in moderately dense flows, namely, two-way coupling in the carrier phase, and the decomposition of the particle-phase velocity into its spatially correlated and uncorrelated components. Specifically, this last contribution allows us to identify in the stochastic model the contributions due to the correlated fluctuating energy and to the granular temperature of the particle phase, which determine the time scale for particle–particle collisions. The model is then validated and assessed against direct-numerical-simulation data for homogeneous configurations of increasing difficulty: (i) homogeneous isotropic turbulence, (ii) decaying and shear turbulence and (iii) CIT.

Comments

This is a manuscript of an article published as Innocenti, A., R. O. Fox, M. V. Salvetti, and S. Chibbaro. "A Lagrangian probability-density-function model for collisional turbulent fluid–particle flows." Journal of Fluid Mechanics 862 (2019): 449-489. doi: 10.1017/jfm.2018.895. Posted with permission.

Copyright Owner

Cambridge University Press

Language

en

File Format

application/pdf

Published Version

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