High-speed digital visualization and high-frequency automated shock tracking in supersonic flows

Brenda H. Timmerman; Andrew J. Skeen; Peter John Bryanston-Cross; Paul G. Tucker; R. J. Jefferson-Loveday; James D. Paduano; G. R. Guenette Jr.

doi:10.1117/1.2992621

1 October 2008 High-speed digital visualization and high-frequency automated shock tracking in supersonic flows

Brenda H. Timmerman, Andrew J. Skeen, Peter John Bryanston-Cross, Paul G. Tucker, R. J. Jefferson-Loveday, James D. Paduano, G. R. Guenette Jr.

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Optical Engineering, Vol. 47, Issue 10, 103201 (October 2008). https://doi.org/10.1117/1.2992621

Abstract

A low-cost, robust, versatile digital shadowgraph visualization system is presented that provides a fast nonintrusive diagnostic for unsteady high-speed flows. The technique is particularly designed for real-time automated tracking of shock positions, enabling high-speed active shock control. The visualization system is based on a high-intensity white LED light source combined with a CMOS-imaging sensor, providing the system with three modes of operation: (1) high-resolution overall instantaneous visualization; (2) high-resolution visualization showing spatial-temporal variations in the flow field, allowing direct identification of areas where changes occur; (3) adjustable windowed visualization at reduced resolution at high frame rate (currently up to 980 Hz). Experimental results are presented together with numerical simulations based on the high-accuracy NTS Navier-Stokes solver and Roe's flux difference splitting method. The flow studied is an adjustable underexpanded jet flow coming from a nozzle that is placed in a counterflowing Mach-2 flow. The interaction of the two flows results in a complex shock and expansion pattern, providing a challenging configuration for the numerical flow solver. By modulating the jet, high-frequency changes are induced in the interaction pattern, allowing simulation of shock movement in a supersonic inlet. Good correspondence between measured and numerical shock position and angle is found.

©(2008) Society of Photo-Optical Instrumentation Engineers (SPIE)

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Brenda H. Timmerman, Andrew J. Skeen, Peter John Bryanston-Cross, Paul G. Tucker, R. J. Jefferson-Loveday, James D. Paduano, and G. R. Guenette Jr. "High-speed digital visualization and high-frequency automated shock tracking in supersonic flows," Optical Engineering 47(10), 103201 (1 October 2008). https://doi.org/10.1117/1.2992621

Published: 1 October 2008

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