Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Suspensions of finite-size neutrally buoyant spheres in turbulent duct 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: 0000-0003-0418-7864
KTH, School of Engineering Sciences (SCI), Mechanics. Ruhr-Universität Bochum, Department of Hydraulic Fluid Machinery, Universitätsstrae 150, Bochum, Germany.
Ruhr Univ Bochum, Chair Hydraul Fluid Machinery, Univ Str 150, D-44801 Bochum, Germany..
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
2018 (English)In: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 851, p. 148-186Article in journal (Refereed) Published
Abstract [en]

We study the turbulent square duct flow of dense suspensions of neutrally buoyant spherical particles. Direct numerical simulations (DNS) are performed in the range of volume fractions phi = 0-0.2, using the immersed boundary method (IBM) to account for the dispersed phase. Based on the hydraulic diameter a Reynolds number of 5600 is considered. We observe that for phi = 0.05 and 0.1, particles preferentially accumulate on the corner bisectors, close to the corners, as also observed for laminar square duct flows of the same duct-to-particle size ratio. At the highest volume fraction, particles preferentially accumulate in the core region. For plane channel flows, in the absence of lateral confinement, particles are found instead to be uniformly distributed across the channel. The intensity of the cross-stream secondary flows increases (with respect to the unladen case) with the volume fraction up to phi = 0.1, as a consequence of the high concentration of particles along the corner bisector. For phi = 0.2 the turbulence activity is reduced and the intensity of the secondary flows reduces to below that of the unladen case. The friction Reynolds number increases with phi in dilute conditions, as observed for channel flows. However, for phi = 0.2 the mean friction Reynolds number is similar to that for phi = 0.1. By performing the turbulent kinetic energy budget, we see that the turbulence production is enhanced up to phi = 0.1, while for phi = 0.2 the production decreases below the values for phi = 0.05. On the other hand, the dissipation and the transport monotonically increase with phi The interphase interaction term also contributes positively to the turbulent kinetic energy budget and increases monotonically with phi, in a similar way as the mean transport. Finally, we show that particles move on average faster than the fluid. However, there are regions close to the walls and at the corners where they lag behind it. In particular, for phi = 0.05, 0.1, the slip velocity distribution at the corner bisectors seems correlated to the locations of maximum concentration: the concentration is higher where the slip velocity vanishes. The wall-normal hydrodynamic and collision forces acting on the particles push them away from the corners. The combination of these forces vanishes around the locations of maximum concentration. The total mean forces are generally low along the corner bisectors and at the core, also explaining the concentration distribution for phi = 0.2.

Place, publisher, year, edition, pages
Cambridge University Press, 2018. Vol. 851, p. 148-186
Keywords [en]
multiphase and particle-laden flows, particle/fluid flows, suspensions
National Category
Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:kth:diva-232760DOI: 10.1017/jfm.2018.490ISI: 000439307100005Scopus ID: 2-s2.0-85050644622OAI: oai:DiVA.org:kth-232760DiVA, id: diva2:1236639
Funder
Swedish e‐Science Research CenterEU, European Research Council, ERC-2013-CoG-616186
Note

QC 20180803

Available from: 2018-08-03 Created: 2018-08-03 Last updated: 2018-11-23Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Authority records BETA

Fornari, WalterBrandt, Luca

Search in DiVA

By author/editor
Fornari, WalterKazerooni, Hamid TabaeiBrandt, Luca
By organisation
MechanicsLinné Flow Center, FLOWSeRC - Swedish e-Science Research Centre
In the same journal
Journal of Fluid Mechanics
Fluid Mechanics and Acoustics

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 104 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf