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Near noise field of a jet-engine exhaust 1: sound pressures

Description: Report presenting information about the acoustical near field produced by the exhaust of a stationary turbojet engine with a high pressure ratio measured for a single operating condition without afterburning. Additional testing was made at a few points to determine the difference in value between sound-pressure levels at rigid surfaces and corresponding free-field values. Results regarding overall sound pressure, sound-pressure level in frequency bands, sound-pressure-level spectra along jet boundary, and second-source noise are provided.
Date: October 1956
Creator: Howes, Walton L. & Mull, Harold R.
Partner: UNT Libraries Government Documents Department

Preliminary flight survey of aerodynamic noise on an airplane wing

Description: Report presenting a brief series of airplane-wing aerodynamic-noise and boundary-layer-profile measurements made in flight as part of an extended investigation of boundary-layer noise. Results regarding the boundary layer data and ratio of root-mean-square sound pressure to the dynamic pressure are provided.
Date: March 2, 1956
Creator: Mull, Harold R. & Algranti, Joseph S.
Partner: UNT Libraries Government Documents Department

Near Noise Field of a Jet-Engine Exhaust

Description: From Summary: "Aircraft structures located in the near noise field of a jet engine are subjected to extremely high fluctuating pressures that may cause structural fatigue. Studies of such structures have been limited by lack of knowledge of the loadings involved. The acoustic near field produced by the exhaust of a stationary turbojet engine having a high pressure ratio was measured for a single operating condition without burning. The maximum overall sound pressure without afterburning was found to be about 42 pounds per square foot along the jet boundary in the region immediately downstream of the jet-nozzle exit."
Date: 1957
Creator: Howes, Walton L.; Callaghan, Edmund E.; Coles, Willard D. & Mull, Harold R.
Partner: UNT Libraries Government Documents Department

Survey of the acoustic near field of three nozzles at a pressure ratio of 30

Description: The sound pressures radiating from the exhaust streams of two convergent-divergent and one convergent nozzle were measured. Exit diameters were 1.206 in. for the expanded nozzle and 0.625 in. for the convergent nozzle. The results are presented in a series of contour maps of overall and fine 1/3-octave-band sound pressures. The location of the source of the noise in each 1/3-octave band in the frequency range of 30 to 16,000 cps and the total power radiated were determined and compared with those of subsonic jets.
Date: April 1957
Creator: Mull, Harold R. & Erickson, John C., Jr.
Partner: UNT Libraries Government Documents Department