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Transition Delay and its Implications for Drag Reduction in Particle-laden Channel Flow
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, Centres, SeRC - Swedish e-Science Research Centre.ORCID iD: 0000-0002-4346-4732
2015 (English)In: International Conference of Computational Methods in Sciences and Engineering (ICCMSE),, American Institute of Physics (AIP), 2015, 180009Conference paper (Refereed)Text
Abstract [en]

Direct numerical simulations of a two-way coupled particle-laden channel flow are performed in the transitional and turbulent regime. Our aim is to investigate whether particles, assumed solid, spherical and heavy delay transition and diminish drag in wall bounded flows. We consider that the only interaction between the carrier and dispersed phase is due to the Stokes drag. The simulations have been performed with a pseudo-spectral solver for the incompressible Navier-Stokes equations while the particle equations are solved in a Lagrangian formulation. In the transitional regime, we study the evolution of disturbances added to a plane Poiseuille base flow with Reynolds number 2000, based on the channel half-height and centerline velocity. By fixing the Reynolds number, the only two free parameters are the particle Stokes number St and the particle mass fraction f. Two different scenarios are considered depending on the initial condition of the velocity field. The first scenario consists of counter-rotating streamwise vortices and one three-dimensional mode while the second is a nonlinear interaction of two symmetric oblique waves. The effects of the particles on the flow transition depend on the particle mass fraction. In particular, at lower concentrations, the transition is facilitated by the presence of the particles, conversely at higher mass fractions the particles tend to stabilize the flow. The results indicate that the particle can play an important role by influencing secondary instabilities and streaks breakdown. These effects can be linked to the reduced drag observed in turbulent channel flow laden with heavy particles and specific simulations in the turbulent regime have been performed.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2015. 180009
Series
, AIP Conference Proceedings, ISSN 0094-243X ; 1702
Keyword [en]
DNS, transition delay, particle laden flows, drag reduction
National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:kth:diva-185115DOI: 10.1063/1.4938958ISI: 000371804300179ISBN: 978-0-7354-1349-8OAI: oai:DiVA.org:kth-185115DiVA: diva2:918753
Conference
International Conference of Computational Methods in Sciences and Engineering (ICCMSE), MAR 20-23, 2015, Athens, GREECE
Note

QC 20160411

Available from: 2016-04-11 Created: 2016-04-11 Last updated: 2016-04-13Bibliographically approved

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Brandt, Luca
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MechanicsLinné Flow Center, FLOWSeRC - Swedish e-Science Research Centre
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ReferencesLink to record
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