Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Effects of the finite particle size in turbulent wall-bounded flows of dense suspensions
Delft Univ Technol, Proc & Energy Dept Multiphase Syst, Leeghwaterstr 21, NL-2621 CA Delft, Netherlands..
Univ Padua, Dept Ind Engn, Via Venezia 1, I-35131 Padua, Italy..
KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Centra, SeRC - Swedish e-Science Research Centre.ORCID-id: 0000-0002-4346-4732
Delft Univ Technol, Proc & Energy Dept Multiphase Syst, Leeghwaterstr 21, NL-2621 CA Delft, Netherlands..
2018 (engelsk)Inngår i: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 843, s. 450-478Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We use interface-resolved numerical simulations to study finite-size effects in turbulent channel flow of neutrally buoyant spheres. Two cases with particle sizes differing by a factor of two, at the same solid volume fraction of 20% and bulk Reynolds number are considered. These are complemented with two reference single-phase flows: the unladen case, and the flow of a Newtonian fluid with the effective suspension viscosity of the same mixture in the laminar regime. As recently highlighted in Costa etal. (Phys. Rev. Lett., vol.117, 2016, 134501), a particle-wall layer is responsible for deviations of the mesoscale-averaged statistics from what is observed in the continuum limit where the suspension is modelled as a Newtonian fluid with (higher) effective viscosity. Here we investigate in detail the fluid and particle dynamics inside this layer and in the bulk. In the particle-wall layer, the near-wall inhomogeneity has an influence on the suspension microstructure over a distance proportional to the particle size. In this layer, particles have a significant (apparent) slip velocity that is reflected in the distribution of wall shear stresses. This is characterized by extreme events (both much higher and much lower than the mean). Based on these observations we provide a scaling for the particle-to-fluid apparent slip velocity as a function of the flow parameters. We also extend the scaling laws in Costa etal. (Phys. Rev. Lett., vol.117, 2016, 134501) to second-order Eulerian statistics in the homogeneous suspension region away from the wall. The results show that finite-size effects in the bulk of the channel become important for larger particles, while negligible for lower-order statistics and smaller particles. Finally, we study the particle dynamics along the wall-normal direction. Our results suggest that single-point dispersion is dominated by particle-turbulence (and not particle-particle) interactions, while differences in two-point dispersion and collisional dynamics are consistent with a picture of shear-driven interactions.

sted, utgiver, år, opplag, sider
CAMBRIDGE UNIV PRESS , 2018. Vol. 843, s. 450-478
Emneord [en]
multiphase and particle-laden flows, particle/fluid flows suspensions, turbulent flows
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-225710DOI: 10.1017/jfm.2018.117ISI: 000428165000001Scopus ID: 2-s2.0-85044259159OAI: oai:DiVA.org:kth-225710DiVA, id: diva2:1196742
Forskningsfinansiär
Swedish Research Council
Merknad

QC 20180411

Tilgjengelig fra: 2018-04-11 Laget: 2018-04-11 Sist oppdatert: 2018-04-11bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler i DiVA

Andre lenker

Forlagets fulltekstScopus

Personposter BETA

Brandt, L.uca

Søk i DiVA

Av forfatter/redaktør
Brandt, L.uca
Av organisasjonen
I samme tidsskrift
Journal of Fluid Mechanics

Søk utenfor DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric

doi
urn-nbn
Totalt: 34 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf