A review of recent developments in schlieren and shadowgraph techniques

Schlieren and shadowgraph techniques are used around the world for imaging and measuring phenomena in transparent media. These optical methods originated long ago in parallel with telescopes and microscopes, and although it might seem that little new could be expected of them on the timescale of 15...

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Bibliographic Details
Published inMeasurement science & technology Vol. 28; no. 4; pp. 42001 - 42025
Main Authors Settles, Gary S, Hargather, Michael J
Format Journal Article
LanguageEnglish
Published IOP Publishing 01.04.2017
Subjects
background-oriented schlieren
digital image processing
flow visualization
high-speed imaging
MATLAB
schlieren
shadowgraph
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Summary:Schlieren and shadowgraph techniques are used around the world for imaging and measuring phenomena in transparent media. These optical methods originated long ago in parallel with telescopes and microscopes, and although it might seem that little new could be expected of them on the timescale of 15 years, in fact several important things have happened that are reviewed here. The digital revolution has had a transformative effect, replacing clumsy photographic film methods with excellent-though expensive-high-speed video cameras, making digital correlation and processing of shadow and schlieren images routine, and providing an entirely-new synthetic schlieren technique that has attracted a lot of attention: background-oriented schlieren or BOS. Several aspects of modern schlieren and shadowgraphy depend upon laptop-scale computer processing of images using an image-capable language such as MATLAB™. BOS, shock-wave tracking, schlieren velocimetry, synthetic streak-schlieren, and straightforward quantitative density measurements in 2D flows are all recent developments empowered by this digital and computational capability.
Bibliography:MST-104662.R2
ISSN:0957-0233
1361-6501
DOI:10.1088/1361-6501/aa5748