Accession Number:

AD0627328

Title:

SMALL SUBMERGED SUPERSONIC GAS JETS. RESULTS OF A SERIES OF EXIT-STABILITY AND NOISE TESTS,

Descriptive Note:

Research rept.,

Corporate Author:

NAVAL ORDNANCE TEST STATION CHINA LAKE CALIF

Personal Author(s):

Report Date:

1966-01-01

Pagination or Media Count:

25.0

Abstract:

High-speed photography revealed that several submerged supersonic gas jets were unstable and broke up into a bubbly water mixture very rapidly upon exit. Jet instability varied in amplitude at a frequency of approximately 300 cps. Over- or underexpansion of the jet did not noticeably affect jet instability. Occasionally, during periods of extremely high-amplitude pulsing, the jet would form a large bubble. The bubble would rapidly expand and disintegrate, generating a pressure wave of high intensity. A frequency spectrum analysis revealed noise with a bandwidth of approximately 50 to 4,500 cps, with a number of reinforced peaks. The spectrum shape varied little with chamber pressure, and therefore was not affected by over- or underexpansion of the gas jet. Neither jet instability nor resonating bubbles contributed noticeably to the noise spectrum. Author

Subject Categories:

  • Acoustics
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE