Dissipative distinctions
Dissipative distinctions
There have been numerous studies concerning the possibility of self-similar scaling laws in fully developed turbulent shear flows, driven over the past half-century or so by the early seminal work of Townsend (1956, The Structure of Turbulent Shear Flow. Cambridge University Press). His and nearly all subsequent analyses depend crucially on a hypothesis about the nature of the dissipation, ?, of turbulence kinetic energy, k. It has usually been assumed (sometimes implicitly) that this is governed by the famous Kolmogorov relation ?=C?k3/2/L, where L is a length scale of the energy-containing eddies and C? is a constant. The paper by Dairay et al. (J. Fluid Mech. vol. 781, 2015, pp. 166–195) demonstrates, however, that, in the specific context of an axisymmetric wake, there can be regions where ? has a different behaviour, characterised by a C? that is not constant but depends on a varying local Reynolds number (despite the existence of a ?5/3 region in the spectra). This leads to fundamentally different scaling laws for the wake.
turbulance theory, wakes
1-4
Castro, I.
66e6330d-d93a-439a-a69b-e061e660de61
February 2016
Castro, I.
66e6330d-d93a-439a-a69b-e061e660de61
Abstract
There have been numerous studies concerning the possibility of self-similar scaling laws in fully developed turbulent shear flows, driven over the past half-century or so by the early seminal work of Townsend (1956, The Structure of Turbulent Shear Flow. Cambridge University Press). His and nearly all subsequent analyses depend crucially on a hypothesis about the nature of the dissipation, ?, of turbulence kinetic energy, k. It has usually been assumed (sometimes implicitly) that this is governed by the famous Kolmogorov relation ?=C?k3/2/L, where L is a length scale of the energy-containing eddies and C? is a constant. The paper by Dairay et al. (J. Fluid Mech. vol. 781, 2015, pp. 166–195) demonstrates, however, that, in the specific context of an axisymmetric wake, there can be regions where ? has a different behaviour, characterised by a C? that is not constant but depends on a varying local Reynolds number (despite the existence of a ?5/3 region in the spectra). This leads to fundamentally different scaling laws for the wake.
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Accepted/In Press date: October 2015
e-pub ahead of print date: 22 December 2015
Published date: February 2016
Keywords:
turbulance theory, wakes
Organisations:
Astronautics Group
Identifiers
Local EPrints ID: 385982
URI: http://eprints.soton.ac.uk/id/eprint/385982
ISSN: 0022-1120
PURE UUID: 46168000-5492-436d-9c94-ee3637aac6b0
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Date deposited: 27 Jan 2016 09:55
Last modified: 14 Mar 2024 22:25
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