ePrints

An experimental study of turbulent vortex rings during their early development

Lookup NU author(s): Dr Lian Gan

Downloads

Full text for this publication is not currently held within this repository. Alternative links are provided below where available.

Abstract

In this paper, the early development of turbulent vortex rings at two Reynolds numbers is studied using two-dimensional and stereoscopic particle image velocimetry (PIV). In the late 1980s, a similarity theory of turbulent vortex rings was proposed and this theory was tested primarily using laser Doppler velocimetry (LDV). However, because of limitations of the experimental technique, the tests were inconclusive and important assumptions could not be checked. Because single-point measurements were used, vortex ring structures could only be inferred using a complex signal analysis technique. In this study, the PIV technique provides spatial measurements of the full field of the cross-section of a ring from which a more rigorous investigation of the similarity theory is possible. Because the region over which the similarity theory appears to hold starts at about 2.5 orifice diameters downstream, this study focusses on the early development region from this point to 8 diameters downstream. Finally, Reynolds stresses and turbulence production contours are presented. The effects of ring dispersion on the measurements is also studied and quantified.

Publication metadata

Author(s): Gan L, Nickels TB

Publication type: Article

Publication status: Published

Journal: Journal of Fluid Mechanics

Year: 2010

Volume: 649

Pages: 467-496

Print publication date: 13/04/2010

ISSN (print): 0022-1120

ISSN (electronic): 1469-7645

Publisher: Cambridge University Press

URL: http://dx.doi.org/10.1017/S0022112009993971

DOI: 10.1017/S0022112009993971

Altmetrics

Share