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Planar shock cylindrical focusing by a perfect-gas lens

Dimotakis, P. E. and Samtaney, R. (2006) Planar shock cylindrical focusing by a perfect-gas lens. Physics of Fluids, 18 (3). Art. No. 031705. ISSN 1070-6631. https://resolver.caltech.edu/CaltechAUTHORS:DIMpof06

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Abstract

We document a gas lensing technique that generates a converging shock wave in a two-dimensional wedge geometry. A successful design must satisfy three criteria at the contact point between the gas lens and the wedge leading edge to minimize nonlinear reflected and other wave effects. The result is a single-point solution in a multidimensional parameter space. The gas lens shape is computed using shock-polar analysis for regular refraction of the incident shock at the gas lens interface. For the range of parameters investigated, the required gas-lens interface is closely matched by an ellipse or hyperbola. Nonlinear Euler simulations confirm the analysis and that the transmitted shock is circular. As the converging transmitted shock propagates down the wedge, its shape remains nearly uniform with less than 0.1% peak departures from a perfect circular cylinder segment. Departure from the design criteria leads to converging shocks that depart from the required shape. The sensitivity to incident shock Mach number, as well as the qualitative effects of the presence of boundary layers are also discussed.


Item Type:Article
ORCID:
AuthorORCID
Samtaney, R.0000-0002-4702-6473
Additional Information:© 2006 American Institute of Physics. Received 15 December 2005; accepted 10 February 2006; published online 17 March 2006. The authors would like to acknowledge discussions with Paul Miller, Omar Hurricane, and Karnig Mikaelian of the Lawrence Livermore National Laboratory (LLNL), as well as discussions and exchanges with Hans Hornung, Dale Pullin, Dan Meiron, Amy Lam, and David Hill of Caltech. This work was performed under the auspices of the U.S. Department of Energy by the U.C. LLNL, under Contract No. W-7405-Eng-48, DOE/Caltech ASC/ASAP Subcontract No. B341492.
Group:GALCIT
Subject Keywords:shock waves; flow simulation; Mach number; boundary layers; aerodynamics
Issue or Number:3
Record Number:CaltechAUTHORS:DIMpof06
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:DIMpof06
Alternative URL:http://dx.doi.org/10.1063/1.2186553
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9135
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:01 Nov 2007
Last Modified:02 Oct 2019 23:57

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