- Title
- Boundedness of the velocity derivative flatness factor in a turbulent plane jet
- Creator
- Tang, S. L.; Antonia, R. A.; Djenidi, L.; Danaila, L.; Zhou, Y.
- Relation
- The 20th Australasian Fluid Mechanics Conference (AFMC). Proceedings of the 20th Australasian Fluid Mechanics Conference (Perth, W.A. 05-06 December, 2016)
- Relation
- http://www.afms.org.au/proceedings/20.html
- Publisher
- Australasian Fluid Mechanics Society (AFMS)
- Resource Type
- conference paper
- Date
- 2016
- Description
- This paper focuses on the statistics of normalized fourth-order moment of the longitudinal velocity derivative, ∂u/∂x, i.e. the flatness factor S4 = (∂u/∂x)4/(∂u/∂x)22 on the axis of a plane jet over a range of Taylor microscale Reynolds number varying between Rλ ' 500 and 1100. The aim is to determine the dependence of S4 on Rλ. Different tests on the jet axis show that local isotropy is closely satisfied, allowing the use of εiso, the locally isotropic form of the mean turbulent kinetic energy dissipation rate ε. The measurements show that S4 remains approximately constant when Rλ ≥ 500. This is inconsistent S4 ∼ Rαλ, where α is a small positive number, as predicted by various internal intermittency models. The constancy of S4 is in full agreement with the relatively recent results (6) showing that S3, the skewness of ∂u/∂x, also tends to a constant when Rλ increases. The present results conform with the original similarity hypotheses of Kolmogorov (1).
- Identifier
- http://hdl.handle.net/1959.13/1476501
- Identifier
- uon:49836
- Identifier
- ISBN:9781740523776
- Language
- eng
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