- Title
- Approach to local axisymmetry in a turbulent cylinder wake
- Creator
- Mi, J.; Antonia, R. A.
- Relation
- Experiments in Fluids Vol. 48, Issue 6, p. 933-947
- Publisher Link
- http://dx.doi.org/10.1007/s00348-009-0779-2
- Publisher
- Springer
- Resource Type
- journal article
- Date
- 2010
- Description
- The objective of this experimental study is to characterise the small-scale turbulence in the intermediate wake of a circular cylinder using measured mean-squared velocity gradients. Seven of the twelve terms which feature in ε, the mean dissipation rate of the turbulent kinetic energy, were measured throughout the intermediate wake at a Reynolds number of Red ≈ 3000 based on the cylinder diameter (d). Earlier measurements of the nine major terms of ε by Browne et al. (J Fluid Mech 179: 307–326 1987) at a downstream distance (x) of x = 420d and Red ≈ 1170 are also used. Whilst departures from local isotropy are significant at all locations in the wake, local axisymmetry of the small-scale turbulence with respect to the mean flow direction is first satisfied approximately at x = 40d. The approach towards local axisymmetry is discussed in some detail in the context of the relative values of the mean-squared velocity gradients. The data also indicate that axisymmetry is approximately satisfied by the large scales at xld ≥ 40, suggesting that the characteristics of the small scales reflect to a major extent those of the large scales. Nevertheless, the far-wake data of Browne et al. (1987) show a discernible departure from axisymmetry for both small and large scales.
- Subject
- local axisymmetry; turbulence; circular cylinder; wake
- Identifier
- http://hdl.handle.net/1959.13/922726
- Identifier
- uon:9626
- Identifier
- ISSN:0723-4864
- Language
- eng
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