Conditional flow statistics and alignment of principal strain rates, vorticity, and scalar gradients in a turbulent nonpremixed jet flame

Antonio Attili, Fabrizio Bisetti

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations

Abstract

The alignment of vorticity and gradients of conserved and reactive scalars with the eigenvectors of the strain rate tensor (i.e., the principal strains) is investigated in a direct numerical simulation of a turbulent nonpremixed flame achieving a Taylor's scale Reynolds number in the range 100 ≤ Reλ ≤ 150 (Attili et al. Comb. Flame, 161, 2014). The vorticity vector displays a pronounced tendency to align with the direction of the intermediate strain. These alignment statistics are in almost perfect agreement with those in homogeneous isotropic turbulence (Ashurst et al. Physics of Fluids 30, 1987) and differ significantly from the results obtained in other nonpremixed flames in which vorticity alignment with the most extensive strain was observed (Boratav et al. Physics of Fluids 8, 1996). The gradients of conserved and reactive scalars align with the most compressive strain. It is worth noting that conditioning on the local values of the mixture fraction, or equivalently conditioning on the distance from the flame sheet, does not affect the statistics. Our results suggest that turbulence overshadows the effects of heat release and chemical reactions. This may be due to the larger Reynolds number achieved in the present study compared to that in previous works.

Original languageEnglish (US)
Title of host publication9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015
PublisherTSFP-9
ISBN (Electronic)9780000000002
StatePublished - 2015
Event9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015 - Melbourne, Australia
Duration: Jun 30 2015Jul 3 2015

Publication series

Name9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015
Volume3

Conference

Conference9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015
Country/TerritoryAustralia
CityMelbourne
Period06/30/1507/3/15

Bibliographical note

KAUST Repository Item: Exported on 2020-04-23

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes

Fingerprint

Dive into the research topics of 'Conditional flow statistics and alignment of principal strain rates, vorticity, and scalar gradients in a turbulent nonpremixed jet flame'. Together they form a unique fingerprint.

Cite this