Properties of vortices in the self-similar turbulent jet

Agrawal, A. ; Prasad, A. (2002) Properties of vortices in the self-similar turbulent jet Experiments in Fluids, 33 (4). pp. 565-577. ISSN 0723-4864

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Official URL: http://doi.org/10.1007/s00348-002-0507-7

Related URL: http://dx.doi.org/10.1007/s00348-002-0507-7

Abstract

Instantaneous, two-dimensional velocity measurements were conducted in the axial plane of a self-similar turbulent axisymmetric jet. The velocity fields were high-pass filtered to expose the vortical structures. An automated method was used to identify the radial and axial coordinates of the vortex centers and rotational sense, and to measure their size, circulation, vorticity, and energy. New insights into turbulent jets are obtained by plotting statistical distributions for vortex properties as functions of Reynolds number and radial position. While the probability of finding a vortex is uniform up to the edge of the jet, the strongest eddies in the high-pass filtered field occur near the jet axis. The average circulation is directly proportional to the vortex size. The Reynolds number strongly affects the average vorticity, circulation, and energy of the eddies. However, the normalized curves show a good collapse implying that the jet is indeed self-similar. Results for the left and right half-planes of the jet are also presented. Interestingly, we find that contrary to customary drawings of jet flows, a substantial number of both clockwise and counter-clockwise rotating eddies exist on both sides of the jet axis, with almost equal numbers of oppositely rotating vortices close to the jet axis. Further, the disparity in the number of oppositely rotating eddies in each half-plane increases with the eddy size. Nevertheless, these results are consistent with the well-known radial vorticity distribution of axisymmetric jets.

Item Type:Article
Source:Copyright of this article belongs to Springer Nature.
Keywords:Vortex, Reynolds Number; Vorticity; Vortical Structure; Vortex Center.
ID Code:115181
Deposited On:17 Mar 2021 07:58
Last Modified:17 Mar 2021 07:58

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