Fluctuations of a passive scalar in a turbulent mixing layer

Handle URI:
http://hdl.handle.net/10754/552133
Title:
Fluctuations of a passive scalar in a turbulent mixing layer
Authors:
Attili, Antonio; Bisetti, Fabrizio ( 0000-0001-5162-7805 )
Abstract:
The turbulent flow originating downstream of the Kelvin-Helmholtz instability in a mixing layer has great relevance in many applications, ranging from atmospheric physics to combustion in technical devices. The mixing of a substance by the turbulent velocity field is usually involved. In this paper, a detailed statistical analysis of fluctuations of a passive scalar in the fully developed region of a turbulent mixing layer from a direct numerical simulation is presented. Passive scalar spectra show inertial ranges characterized by scaling exponents −4/3 and −3/2 in the streamwise and spanwise directions, in agreement with a recent theoretical analysis of passive scalar scaling in shear flows [Celani et al., J. Fluid Mech. 523, 99 (2005)]. Scaling exponents of high-order structure functions in the streamwise direction show saturation of intermittency with an asymptotic exponent ζ∞=0.4 at large orders. Saturation of intermittency is confirmed by the self-similarity of the tails of the probability density functions of the scalar increments at different scales r with the scaling factor r−ζ∞ and by the analysis of the cumulative probability of large fluctuations. Conversely, intermittency saturation is not observed for the spanwise increments and the relative scaling exponents agree with recent results for homogeneous isotropic turbulence with mean scalar gradient. Probability density functions of the scalar increments in the three directions are compared to assess anisotropy.
KAUST Department:
Clean Combustion Research Center
Citation:
Fluctuations of a passive scalar in a turbulent mixing layer 2013, 88 (3) Physical Review E
Journal:
Physical Review E
Issue Date:
19-Sep-2013
DOI:
10.1103/PhysRevE.88.033013
Type:
Article
ISSN:
1539-3755; 1550-2376
Additional Links:
http://link.aps.org/doi/10.1103/PhysRevE.88.033013
Appears in Collections:
Articles; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorAttili, Antonioen
dc.contributor.authorBisetti, Fabrizioen
dc.date.accessioned2015-05-03T14:20:14Zen
dc.date.available2015-05-03T14:20:14Zen
dc.date.issued2013-09-19en
dc.identifier.citationFluctuations of a passive scalar in a turbulent mixing layer 2013, 88 (3) Physical Review Een
dc.identifier.issn1539-3755en
dc.identifier.issn1550-2376en
dc.identifier.doi10.1103/PhysRevE.88.033013en
dc.identifier.urihttp://hdl.handle.net/10754/552133en
dc.description.abstractThe turbulent flow originating downstream of the Kelvin-Helmholtz instability in a mixing layer has great relevance in many applications, ranging from atmospheric physics to combustion in technical devices. The mixing of a substance by the turbulent velocity field is usually involved. In this paper, a detailed statistical analysis of fluctuations of a passive scalar in the fully developed region of a turbulent mixing layer from a direct numerical simulation is presented. Passive scalar spectra show inertial ranges characterized by scaling exponents −4/3 and −3/2 in the streamwise and spanwise directions, in agreement with a recent theoretical analysis of passive scalar scaling in shear flows [Celani et al., J. Fluid Mech. 523, 99 (2005)]. Scaling exponents of high-order structure functions in the streamwise direction show saturation of intermittency with an asymptotic exponent ζ∞=0.4 at large orders. Saturation of intermittency is confirmed by the self-similarity of the tails of the probability density functions of the scalar increments at different scales r with the scaling factor r−ζ∞ and by the analysis of the cumulative probability of large fluctuations. Conversely, intermittency saturation is not observed for the spanwise increments and the relative scaling exponents agree with recent results for homogeneous isotropic turbulence with mean scalar gradient. Probability density functions of the scalar increments in the three directions are compared to assess anisotropy.en
dc.relation.urlhttp://link.aps.org/doi/10.1103/PhysRevE.88.033013en
dc.rightsArchived with thanks to Physical Review Een
dc.titleFluctuations of a passive scalar in a turbulent mixing layeren
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.identifier.journalPhysical Review Een
dc.eprint.versionPublisher's Version/PDFen
kaust.authorAttili, Antonioen
kaust.authorBisetti, Fabrizioen
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