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The Sensitivity and Range Required in a Toepler Schlieren Apparatus for Photography of High-Speed Air Flow

Published online by Cambridge University Press:  07 June 2016

W. A. Mair
W. A. Mair*
Affiliation:
Fluid Motion Laboratory, University of Manchester
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Summary

A simple theoretical analysis is given of the quantities affecting the sensitivity and range of a schlieren apparatus. In regions of large density gradient the deflections of the light rays may lie outside the normal working range. When this occurs, dark regions may appear in parts of the photograph that would normally be light. Examples of this effect are given, and it is shown that confusion can be avoided by taking photographs in pairs, with the knife edges or slits arranged to give sensitivities of opposite sign.

The deflections of light rays in various typical disturbances in a supersonic air stream are calculated, using geometrical optics. Prandtl-Meyer expansions, boundary layers, and plane and curved shock waves are considered. From these calculated deflections it is shown that some of the anomalous effects commonly observed in schlieren photographs can be explained.

Type
Research Article
Information
Aeronautical Quarterly , Volume 4 , Issue 1 , February 1954 , pp. 19 - 50
Copyright
Copyright © Royal Aeronautical Society. 1954

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References

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