Comparison of turbulent jets issuing from rectangular nozzles with and without sidewalls

Deo, Ravinesh C. and Nathan, Graham J. and Mi, Jianchun (2007) Comparison of turbulent jets issuing from rectangular nozzles with and without sidewalls. Experimental Thermal and Fluid Science, 32 (2). pp. 596-606. ISSN 0894-1777

Abstract

This paper reports a systematic study of a turbulent jet issuing from a rectangular slot nozzle of high-aspect ratio, AR (w/h, where w and h are the long and short sides of the slot, respectively) tested with and without sidewalls. The solid sidewalls were flush with each of the slot’s short sides vertically and extend axially along the streamwise direction of the jet. Hot-wire measurements were conducted at a Reynolds number based on slot-width (h) and exit centerline velocity of Reh 7000 (for AR = 30 and 60) and at 10,000 (for AR = 30) up to 160 h downstream. All jets have a potential core in which the local centerline velocity is approximately constant, followed by a transition region and then a statistically two-dimensional (2-D) region where the centerline mean velocity, Uc x1/2. The potential core of the jet without sidewalls is shorter than that with sidewalls. Near field power spectral analysis reveals that the primary vortex shedding rate is higher for the jet without sidewalls than the jet with sidewalls. The 2-D region of the jet with sidewalls is found to extend over a longer axial distance than that of the jet without sidewalls. It is also demonstrated that both the decay and spread rates of the jet within the 2-D region are lower for the case with sidewalls. Beyond the 2-D region, the jet without sidewalls enters into a far field transitional phase and then tends to behave statistically like an axisymmetric jet with Uc x1. The centerline turbulence intensity of the jet with sidewalls becomes asymptotic closer to the nozzle exit than the jet without sidewalls. The skewness and flatness factors confirm further statistical differences between the jet with and without sidewalls.


Statistics for USQ ePrint 7403
Statistics for this ePrint Item
Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Awaiting Author's version, which may be deposited in accordance with the copyright policy of the publisher.
Depositing User: Dr Ravinesh C Deo
Faculty / Department / School: Historic - Faculty of Sciences - Department of Maths and Computing
Date Deposited: 14 Apr 2010 10:22
Last Modified: 02 Jul 2013 23:46
Uncontrolled Keywords: plane jet; planar jet; rectangular jet; effect of sidewalls
Fields of Research (FOR2008): 09 Engineering > 0915 Interdisciplinary Engineering > 091508 Turbulent Flows
09 Engineering > 0913 Mechanical Engineering > 091399 Mechanical Engineering not elsewhere classified
09 Engineering > 0915 Interdisciplinary Engineering > 091504 Fluidisation and Fluid Mechanics
Socio-Economic Objective (SEO2008): E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
Identification Number or DOI: doi: 10.1016/j.expthermflusci.2007.06.009
URI: http://eprints.usq.edu.au/id/eprint/7403

Actions (login required)

View Item Archive Repository Staff Only