Simulation of a complete reflected shock tunnel showing a vortex mechanism for flow contamination

Goozee, R. J. and Jacobs, P. A. and Buttsworth, D. R. (2006) Simulation of a complete reflected shock tunnel showing a vortex mechanism for flow contamination. Shock Waves, 15 (3-4). pp. 165-176. ISSN 0938-1287

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Abstract

Simulations of a complete reflected shock tunnel facility have been performed with the aim of providing a better understanding of the flow through these facilities. In particular, the analysis is focused on the premature contamination of the test flow with the driver gas. The axisymmetric simulations model the full geometry of the shock tunnel and incorporate an iris-based model of the primary diaphragm rupture mechanics, an ideal secondary diaphragm and account for turbulence in the shock tube boundary layer with the Baldwin-Lomax eddy viscosity model. Two operating conditions were examined: one resulting in an overtailored mode of operation and the other resulting in approximately tailored operation. The accuracy of the simulations is assessed through comparison with experimental measurements of static pressure, pitot pressure and stagnation temperature. It is shown that the widely-accepted driver gas contamination mechanism in which driver gas jets along the walls through action of the bifurcated foot of the reflected shock, does not directly transport the driver gas to the nozzle at these conditions. Instead, driver gas laden vortices are generated by the bifurcated reflected shock. These vortices prevent jetting of the driver gas along the walls and convect driver gas away from the shock tube wall and downstream into the nozzle. Additional vorticity generated by the interaction of the reflected shock and the contact surface enhances the process in the over-tailored case. However, the basic mechanism appears to operate in a similar way for both the over-tailored and the approximately tailored conditions.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Deposited in accordance with the copyright policy of the publisher. Copyright 2006 Springer Verlag. The original publication is available at www.springerlink.com
Depositing User: Assoc Prof David Buttsworth
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Mechanical and Mechatronic Engineering
Date Deposited: 11 Oct 2007 00:34
Last Modified: 02 Jul 2013 22:35
Uncontrolled Keywords: shock tunnel; driver gas contamination; bifurcated reflected shock
Fields of Research (FOR2008): 02 Physical Sciences > 0203 Classical Physics > 020303 Fluid Physics
02 Physical Sciences > 0203 Classical Physics > 020304 Thermodynamics and Statistical Physics
09 Engineering > 0915 Interdisciplinary Engineering > 091508 Turbulent Flows
Socio-Economic Objective (SEO2008): E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
Identification Number or DOI: doi: 10.1007/s00193-006-0015-4
URI: http://eprints.usq.edu.au/id/eprint/1068

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