Effects of dual jets distance on mixing characteristics and flow path within a cavity in supersonic crossflow

Ukai, T., Zare-Behtash, H. , Lo, K. H., Kontis, K. and Obayashi, S. (2014) Effects of dual jets distance on mixing characteristics and flow path within a cavity in supersonic crossflow. International Journal of Heat and Fluid Flow, 50, pp. 254-262. (doi:10.1016/j.ijheatfluidflow.2014.08.009)

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Publisher's URL: http://dx.doi.org/10.1016/j.ijheatfluidflow.2014.08.009

Abstract

A rectangular open cavity with upstream dual injectors at a freestream Mach number of 1.9 was investigated experimentally. To evaluate the effect of the distance between the jets, the flow characteristics were investigated using the high-speed schlieren photography, particle image velocimetry, and surface oil flow techniques. The dual jet distances of 18 and 54 mm were used. Unstable flow occurs over the cavity in all cases and is not improved by changing the distance between the dual jets. Although the distance between the dual jets does not influence the flow stability, the flow field varies decidedly depending on the dual jets distance. The enhancement of air mixing depends on the distance between the jets. A long dual jets distance was found to yield better mixing characteristics within the cavity than a short one. When the jets are further apart, the mainstream between two counter-rotating vortex pairs behind the jets flows strongly into the cavity because of the increased blow-down occurring between the vortex pairs. Additionally, a counterflow with a low velocity magnitude occurs behind the jets. Hence, mixing is enhanced within the cavity by effects of the opposed flow. When the jet pairs are closer to each other, the counter-rotating vortex pairs are in contact; as a result, the blow-down effect does not occur between them. The flow drawn into the cavity from the mainstream is supplied from the sides of the test section into the cavity.

Item Type:Articles
Additional Information:NOTICE: this is the author’s version of a work that was accepted for publication in International Journal of Heat and Fluid Flow. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Journal of Heat and Fluid Flow, [50, (December 2014)] http://dx.doi.org/10.1016/j.ijheatfluidflow.2014.08.009
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Ukai, Dr Takahiro and Kontis, Professor Konstantinos and Lo, Dr Kin Hing and Zare-Behtash, Dr Hossein
Authors: Ukai, T., Zare-Behtash, H., Lo, K. H., Kontis, K., and Obayashi, S.
Subjects:Q Science > Q Science (General)
Q Science > QC Physics
T Technology > TA Engineering (General). Civil engineering (General)
T Technology > TJ Mechanical engineering and machinery
College/School:College of Science and Engineering > School of Engineering > Aerospace Sciences
Journal Name:International Journal of Heat and Fluid Flow
Publisher:Elsevier
ISSN:0142-727X
ISSN (Online):1879-2278
Copyright Holders:Copyright © 2014 Elsevier Inc.
First Published:First published in International Journal of Heat and Fluid Flow 50:254-262
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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