On BOS and its progenitor, the Background-Distortion Schlieren Technique
Pennsylvania State University
Abstract
Background-Oriented Schlieren (BOS) is an experimental optical approach for imaging transparent phenomena in fluids (for example) by their distortion of a patterned background. It has been around for about 25 years and has attracted a lot of attention and many hundreds of publications. It’s easy to do and lots of fun, it has some notable advantages over traditional optical instruments for flow visualization, and it also has a couple of drawbacks that need to be recognized. This talk is a broad overview of BOS, with some additional comments on refractive optical phenomena that can be seen by background distortion using only the unaided eye and one BOS variant that has become a popular table-top photography hobby.
About the speaker
Dr. Gary Settles earned his Ph.D. degree in Mechanical and Aerospace Engineering at Princeton University in 1976. After a research position at Princeton, he accepted an Assistant Professorship in Mechanical Engineering at Penn State University in 1983. In the ensuing 32 years at Penn State he educated 20 Ph.D. students and a great many Master’s degree and undergraduate students, and he wrote or co-authored many publications on gas dynamics, optical flow diagnostics, shock wave/boundary-layer interactions, and industrial applications of compressible flow. Settles retired from Penn State in 2015. He is best known for his 2001 book on schlieren and shadowgraph techniques, for which a second edition is currently in preparation.
