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Interface-resolved simulations of small inertial particles in turbulent channel flow

Interface-resolved simulations of small inertial particles in turbulent channel flow

Title: Interface-resolved simulations of small inertial particles in turbulent channel flow
Author: Costa, Pedro   orcid.org/0000-0001-7010-1040
Brandt, Luca   orcid.org/0000-0002-4346-4732
picano, francesco   orcid.org/0000-0002-3943-8187
Date: 2019-11-29
Language: English
Scope: A54
University/Institute: Háskóli Íslands
University of Iceland
School: Verkfræði- og náttúruvísindasvið (HÍ)
School of Engineering and Natural Sciences (UI)
Department: Iðnaðarverkfræði-, vélaverkfræði- og tölvunarfræðideild (HÍ)
Faculty of Industrial Eng., Mechanical Eng. and Computer Science (UI)
Series: Journal of Fluid Mechanics;883
ISSN: 0022-1120
1469-7645 (eISSN)
DOI: 10.1017/jfm.2019.918
Subject: Mechanical Engineering; Mechanics of Materials; Condensed Matter Physics; Multiphase flow; Particle/fluid flows; Vélaverkfræði; Þéttefnisfræði
URI: https://hdl.handle.net/20.500.11815/1881

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Costa, P., Brandt, L., & Picano, F. (2020). Interface-resolved simulations of small inertial particles in turbulent channel flow. Journal of Fluid Mechanics, 883, A54. doi:10.1017/jfm.2019.918


We present a direct comparison between interface-resolved and one-way-coupled point-particle direct numerical simulations (DNS) of gravity-free turbulent channel flow laden with small inertial particles, with high particle-to-fluid density ratio and diameter of approximately three viscous units. The most dilute flow considered, solid volume fraction , shows the particle feedback on the flow to be negligible, whereas differences with respect to the unladen case, notably a drag increase of approximately 10 %, are found for a volume fraction. This is attributed to a dense layer of particles at the wall, caused by turbophoresis, flowing with large particle-to-fluid apparent slip velocity. The most dilute case is therefore taken as the benchmark for assessing the validity of a widely used point-particle model, where the particle dynamics results only from inertial and nonlinear drag forces. In the bulk of the channel, the first- and second-order moments of the particle velocity from the point-particle DNS agree well with those from the interface-resolved DNS. Close to the wall, however, most of the statistics show major qualitative differences. We show that this difference originates from the strong shear-induced lift force acting on the particles in the near-wall region. This mechanism is well captured by the lift force model due to Saffman (J. Fluid Mech., vol. 22 (2), 1965, pp. 385-400), while other widely used, more elaborate, approaches aiming at extending the lift model for a wider range of particle Reynolds numbers can actually underpredict the magnitude of the near-wall particle velocity fluctuations for the cases analysed here.


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This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited

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