Please use this identifier to cite or link to this item:
https://hdl.handle.net/2440/52065
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Type: | Journal article |
Title: | The influence of Reynolds number on a plane jet |
Author: | Deo, R. Mi, J. Nathan, G. |
Citation: | Physics of Fluids, 2008; 20(7):075108-01-075108-16 |
Publisher: | Amer Inst Physics |
Issue Date: | 2008 |
ISSN: | 1070-6631 1089-7666 |
Statement of Responsibility: | Ravinesh C. Deo, Jianchun Mi, and Graham J. Nathan |
Abstract: | <jats:p>The present study systematically investigates through experiments the influence of Reynolds number on a plane jet issuing from a radially contoured, rectangular slot nozzle of large aspect ratio. Detailed velocity measurements were performed for a jet exit Reynolds number spanning the range 1500≤Reh≤16 500, where Reh≡Ubh/υ with Ub as the momentum-averaged exit mean velocity, h as the slot height, and υ as the kinematic viscosity. Additional centerline measurements were also performed for jets from two different nozzles in the same facility to achieve Reh=57 500. All measurements were conducted using single hot-wire anemometry to an axial distance (x) of x≤160h. These measurements revealed a significant dependence of the exit and the downstream flows on Reh despite all exit velocity profiles closely approximating a “top-hat” shape. The effect of Reh on both the mean and turbulent fields is substantial for Reh&lt;10 000 but becomes weaker with increasing Reh. The length of the jet’s potential core, initial primary-vortex shedding frequency, and far-field rates of decay and spread all depend on Reh. The local Reynolds number, Rey0.5≡2Ucy0.5/υ, where Uc and y0.5 are the local centerline velocity and half-width, respectively, are found to scale as Rey0.5∼x1/2. It is also shown that, for Reh≥1500, self-preserving relations of both the turbulence dissipation rate (ε) and smallest scale (η), i.e., ε∼Reh3(x/h)−5/2 and η∼Reh−3/4(x/h)5/8, become valid for x/h≥20.</jats:p> |
Rights: | © 2008 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. |
DOI: | 10.1063/1.2959171 |
Published version: | http://dx.doi.org/10.1063/1.2959171 |
Appears in Collections: | Aurora harvest Environment Institute Leaders publications Mechanical Engineering publications |
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hdl_52065.pdf | Published version | 1.08 MB | Adobe PDF | View/Open |
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