CONDITIONAL FLOW STATISTICS AND ALIGNMENT OF PRINCIPAL STRAIN RATES, VORTICITY, AND SCALAR GRADIENTS IN A TURBULENT NONPREMIXED JET FLAME

Handle URI:
http://hdl.handle.net/10754/566966
Title:
CONDITIONAL FLOW STATISTICS AND ALIGNMENT OF PRINCIPAL STRAIN RATES, VORTICITY, AND SCALAR GRADIENTS IN A TURBULENT NONPREMIXED JET FLAME
Authors:
Attili, Antonio; Bisetti, Fabrizio ( 0000-0001-5162-7805 )
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 (Boratavet 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.
KAUST Department:
Clean Combustion Research Center
Journal:
Proceedings of Ninth International Symposium on Turbulence and Shear Flow Phenomena (TSFP-9)
Conference/Event name:
Ninth International Symposium on Turbulence and Shear Flow Phenomena (TSFP-9)
Issue Date:
30-Jun-2015
Type:
Conference Paper
Additional Links:
ftp://tepeu.sisal.unam.mx/TSFP9/full_paper/8C-4.pdf
Appears in Collections:
Conference Papers; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorAttili, Antonioen
dc.contributor.authorBisetti, Fabrizioen
dc.date.accessioned2015-08-13T11:29:08Zen
dc.date.available2015-08-13T11:29:08Zen
dc.date.issued2015-06-30en
dc.identifier.urihttp://hdl.handle.net/10754/566966en
dc.description.abstractThe 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 (Boratavet 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.en
dc.relation.urlftp://tepeu.sisal.unam.mx/TSFP9/full_paper/8C-4.pdfen
dc.titleCONDITIONAL FLOW STATISTICS AND ALIGNMENT OF PRINCIPAL STRAIN RATES, VORTICITY, AND SCALAR GRADIENTS IN A TURBULENT NONPREMIXED JET FLAMEen
dc.typeConference Paperen
dc.contributor.departmentClean Combustion Research Centeren
dc.identifier.journalProceedings of Ninth International Symposium on Turbulence and Shear Flow Phenomena (TSFP-9)en
dc.conference.dateJune 30 - July 3, 2015en
dc.conference.nameNinth International Symposium on Turbulence and Shear Flow Phenomena (TSFP-9)en
dc.conference.locationThe University of Melbourne, Australiaen
dc.eprint.versionPublisher's Version/PDFen
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