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Direct numerical simulation of axisymmetric wakes embedded in turbulence

Published online by Cambridge University Press:  29 August 2012

Elad Rind
Affiliation:
Aeronautics, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, UK
Ian P. Castro*
Affiliation:
Aeronautics, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, UK
*
Email address for correspondence: [email protected]

Abstract

Direct numerical simulation has been used to study the effects of external turbulence on axisymmetric wakes. In the absence of such turbulence, the time-developing axially homogeneous wake is found to have the self-similar properties expected whereas, in the absence of the wake, the turbulence fields had properties similar to Saffman-type turbulence. Merging of the two flows was undertaken for three different levels of external turbulence (relative to the wake strength) and it is shown that the presence of the external turbulence enhances the decay rate of the wake, with the new decay rates increasing with the relative strength of the initial external turbulence. The external turbulence is found to destroy any possibility of self-similarity within the developing wake, causing a significant transformation in the latter as it gradually evolves towards the former.

Type
Papers
Copyright
Copyright © Cambridge University Press 2012

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