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Inertia-driven particle migration and mixing in a wall-bounded laminar suspension flow

Loisel, Vincent and Abbas, Micheline and Masbernat, Olivier and Climent, Éric Inertia-driven particle migration and mixing in a wall-bounded laminar suspension flow. (2015) Physics of Fluids, 27 (12). 123304. ISSN 1070-6631

(Document in English)

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Official URL: http://dx.doi.org/10.1063/1.4936402


Laminar pressure-driven suspensionflows are studied in the situation of neutrally buoyant particles at finite Reynolds number. The numerical method is validated for homogeneous particle distribution (no lateral migration across the channel): the increase of particle slip velocities and particle stress with inertia and concentration is in agreement with former works in the literature. In the case of a two-phase channel flow with freely moving particles, migration towards the channel walls due to the Segré-Silberberg effect is observed, leading to the development of a non-uniform concentration profile in the wall-normal direction (the concentration peaks in the wall region and tends towards zero in the channel core). The particle accumulation in the region of highest shear favors the shear-induced particle interactions and agitation, the profile of which appears to be correlated to the concentration profile. A 1D model predicting particle agitation, based on the kinetic theory of granular flows in the quenched state regime when Stokes number St = O(1) and from numerical simulations when St < 1, fails to reproduce the agitation profile in the wall normal direction. Instead, the existence of secondary flows is clearly evidenced by long time simulations. These are composed of a succession of contra-rotating structures, correlated with the development of concentration waves in the transverse direction. The mechanism proposed to explain the onset of this transverse instability is based on the development of a lift force induced by spanwise gradient of the axial velocity fluctuations. The establishment of the concentration profile in the wall-normal direction therefore results from the combination of the mean flow Segré-Silberberg induced migration, which tends to stratify the suspension and secondary flows which tend to mix the particles over the channel cross section.

Item Type:Article
Additional Information:Thanks to AIP Publishing. The definitive version is available at http://scitation.aip.org The original PDF of the article can be found at Physics of Fluids website : http://scitation.aip.org/content/aip/journal/pof2/27/12/10.1063/1.4936402
HAL Id:hal-01302601
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 - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
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Deposited On:14 Apr 2016 14:08

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