In:
The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 34, No. 12_Supplement ( 1962-12-01), p. 1984-1984
Abstract:
Phased sequences of spark-schlieren photographs have revealed several interesting aspects of the periodic-flow phenomena of the Hartmann whistle, supplementing quantitative acoustical and fluid-flow measurements. The periodic debouching of the fluid occurs in the form of a powerful vortex ring, the normal shockwave near the mouth of the resonant cavity oscillating impulsively through a large amplitude. A second normal shockwave periodically traverses the high-amplitude oscillatory “standing-wave” motion between the external normal shockwave and the end of the cavity. As a result, a periodic, impulsively starting, high-temperature air jet will be emitted from any small aperture at the end of the cavity. There is also evidence of feedback action of the sound field from the nozzle to cavity. It has been discovered that an unstable oscillatory condition also occurs over a limited range of subsonic jet speeds for certain locations of the cavity with respect to the nozzle; this range is greatly increased by the presence of a wake-producing trip or of a local reflecting surface. [This work was supported by the Office of Naval Research, under contract.]
Type of Medium:
Online Resource
ISSN:
0001-4966
,
1520-8524
Language:
English
Publisher:
Acoustical Society of America (ASA)
Publication Date:
1962
detail.hit.zdb_id:
1461063-2
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