Regeneration mechanism of streaks in near-wall quasi-2D turbulence
Regeneration mechanism of streaks in near-wall quasi-2D turbulence
A direct numerical simulation of quasi-2D (that is with flow variables independent of streamwise direction) decaying and forced turbulent flow in a channel was performed in order to seek out the sustenance mechanism of near-wall turbulence by uncovering the mechanism of streak formation. We found the existence of streaks in quasi-2D turbulent flows, thereby demonstrating that feedback from longitudinal flow is not necessary for streak formation. Passive scalars having different mean profiles were introduced in forced quasi-2D turbulent flows in order to compare the streak spacing of the scalars deduced from two-point correlations of DNS results with those obtained from optimal perturbation and Reynolds normal stress anisotropy instability mechanisms. It has been found that although for all the passive scalars the vortex structure is the same, there is a marked variation in streak spacing of the scalars implying that the preferential streak spacing is not necessarily linked to the preferential vortex spacing.
streak spacing, quasi-2D forced turbulence, reynolds normal stresses anisotropy, optimal perturbations, passive scalars
727-736
Baig, M.F.
e618bead-e673-4726-a3ad-ee307203a9a0
Chernyshenko, S.I.
6fef97f7-e668-45f7-8fef-7a4cd4cb1fb2
2004
Baig, M.F.
e618bead-e673-4726-a3ad-ee307203a9a0
Chernyshenko, S.I.
6fef97f7-e668-45f7-8fef-7a4cd4cb1fb2
Baig, M.F. and Chernyshenko, S.I.
(2004)
Regeneration mechanism of streaks in near-wall quasi-2D turbulence.
European Journal of Mechanics - B/Fluids, 23 (5), .
(doi:10.1016/j.euromechflu.2004.02.004).
Abstract
A direct numerical simulation of quasi-2D (that is with flow variables independent of streamwise direction) decaying and forced turbulent flow in a channel was performed in order to seek out the sustenance mechanism of near-wall turbulence by uncovering the mechanism of streak formation. We found the existence of streaks in quasi-2D turbulent flows, thereby demonstrating that feedback from longitudinal flow is not necessary for streak formation. Passive scalars having different mean profiles were introduced in forced quasi-2D turbulent flows in order to compare the streak spacing of the scalars deduced from two-point correlations of DNS results with those obtained from optimal perturbation and Reynolds normal stress anisotropy instability mechanisms. It has been found that although for all the passive scalars the vortex structure is the same, there is a marked variation in streak spacing of the scalars implying that the preferential streak spacing is not necessarily linked to the preferential vortex spacing.
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Published date: 2004
Keywords:
streak spacing, quasi-2D forced turbulence, reynolds normal stresses anisotropy, optimal perturbations, passive scalars
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Local EPrints ID: 23030
URI: http://eprints.soton.ac.uk/id/eprint/23030
ISSN: 0997-7546
PURE UUID: fe98e113-044a-47bd-8296-a6cd02dfc7c0
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Date deposited: 23 Mar 2006
Last modified: 15 Mar 2024 06:43
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Author:
M.F. Baig
Author:
S.I. Chernyshenko
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