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Ballistic range experiments on superbooms generated by refractionThe enhanced sonic boom or supersonic boom generated as a result of atmospheric refraction in threshold Mach number flights was recreated in a ballistic range by firing projectiles at low supersonic speeds into a stratified medium obtained by slowly injecting carbon dioxide into air. The range was equipped with a fast-response dynamic pressure transducer and schlieren photographic equipment, and the sound speed variation with height was controlled by regulating the flow rate of the CO2. The schlieren observations of the resulting flow field indicate that the generated shocks are reflected near the sonic cutoff altitude where local sound speed equals body speed, provided such an altitude exists. Maximum shock strength occurs very nearly at the point where the incident and reflected shocks join, indicating that the presence of the reflected shock may have an appreciable effect on the magnitude of the focus factor. The largest focus factor detected was 1.7 and leads to an estimate that the constant in the Guiraud-Thery scaling law should have a value of 1.30.
Document ID
19760043780
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Sanai, M.
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Toong, T.-Y.
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Pierce, A. D.
(MIT Cambridge, Mass., United States)
Date Acquired
August 8, 2013
Publication Date
March 1, 1976
Publication Information
Publication: Acoustical Society of America
Subject Category
Acoustics
Accession Number
76A26746
Funding Number(s)
CONTRACT_GRANT: NGR-22-009-618
Distribution Limits
Public
Copyright
Other

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