- Title
- On the normalized dissipation parameter C-epsilon in decaying turbulence
- Creator
- Djenidi, L.; Lefeuvre, N.; Kamruzzaman, M.; Antonia, R. A.
- Relation
- Journal of Fluid Mechanics Vol. 817, p. 61-79
- Publisher Link
- http://dx.doi.org/10.1017/jfm.2017.110
- Publisher
- Cambridge University Press
- Resource Type
- journal article
- Date
- 2017
- Description
- The Reynolds number dependence of the non-dimensional mean turbulent kinetic energy dissipation rate C𝜖 =̅∈L/u'³(where 𝜖 is the mean turbulent kinetic energy dissipation rate, is an integral length scale and is the velocity root-mean-square) is investigated in decaying turbulence. Expressions for C𝜖 in homogeneous isotropic turbulent (HIT), as approximated by grid turbulence, and in local HIT, as on the axis of the far field of a turbulent round jet, are developed from the Navier–Stokes equations within the framework of a scale-by-scale energy budget. The analysis shows that when turbulence decays/evolves in compliance with self-preservation (SP), C𝜖 remains constant for a given flow condition, e.g. a given initial Reynolds number. Measurements in grid turbulence, which does not satisfy SP, and on the axis in the far field of a round jet, which does comply with SP, show that C𝜖 decreases in the former case and remains constant in the latter, thus supporting the theoretical results. Further, while C𝜖 can remain constant during the decay for a given initial Reynolds number, both the theory and measurements show that it decreases towards a constant, C𝜖, as Re𝜆 increases. This trend, in agreement with existing data, is not inconsistent with the possibility that C𝜖 tends to a universal constant.
- Subject
- homogeneous turbulence; isotropic turbulence; turbulence theory
- Identifier
- http://hdl.handle.net/1959.13/1399568
- Identifier
- uon:34634
- Identifier
- ISSN:0022-1120
- Language
- eng
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