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The effect of neutrally buoyant finite-size particles on channel flows in the laminar-turbulent transition regime

Loisel, Vincent and Abbas, Micheline and Masbernat, Olivier and Climent, Eric The effect of neutrally buoyant finite-size particles on channel flows in the laminar-turbulent transition regime. (2013) Physics of Fluids, vol. 25 (n° 12). ISSN 1070-6631

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Official URL: http://dx.doi.org/10.1063/1.4848856

Abstract

The presence of finite-size particles in a channel flow close to the laminar-turbulent transition is simulated with the Force Coupling Method which allows two-way coupling with the flow dynamics. Spherical particles with channel height-to-particle diameter ratio of 16 are initially randomly seeded in a fluctuating flow above the critical Reynolds number corresponding to single phase flow relaminarization. When steady-state is reached, the particle volume fraction is homogeneously distributed in the channel cross-section (φ=5%) except in the near-wall region where it is larger due to inertia-driven migration. Turbulence statistics (intensity of velocity fluctuations, small-scale vortical structures, wall shear stress) calculated in the fully coupled two-phase flow simulations are compared to single-phase flow data in the transition regime. It is observed that particles increase the transverse r.m.s. flow velocity fluctuations and they break down the flow coherent structures into smaller, more numerous and sustained eddies, preventing the flow to relaminarize at the single-phase critical Reynolds number. When the Reynolds number is further decreased and the suspension flow becomes laminar, the wall friction coefficient recovers the evolution of the laminar single-phase law provided that the suspension viscosity is used in the Reynolds number definition. The residual velocity fluctuations in the suspension correspond to a regime of particulate shear-induced agitation

Item Type:Article
Additional Information:Thanks to American Institute of Physics editor. The original PDF of the article can be found at Physics of Fluids website : http://scitation.aip.org/content/aip/journal/pof2;jsessionid=610icgaol01ls.x-aip-live-02
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
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Deposited By: Eric CLIMENT
Deposited On:06 Jan 2014 09:11

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