Accession Number : ADP007518

Title :   Comparison of Flyover Noise Data From Aircraft at High Subsonic Speeds with Prediction,

Corporate Author : DEUTSCHE FORSCHUNGSANSTALT FUER LUFT- UND RAUMFAHRT E V BRUNSWICK (GERMANY F R)

Personal Author(s) : Boettcher, J. ; Michel, U.

Report Date : APR 1992

Pagination or Media Count : 12

Abstract : Flyover noise measurements are evaluated for four different military jet aircraft types flying at low altitudes. Flight Mach numbers ranged from 0.5 to 0.9. The analysis shows that noise immission is caused by jet mixing and broadband shock associated noise. Based on the experimental results existing noise prediction schemes are extended toward higher subsonic flight Mach numbers. The novel prediction schemes describe the observed acoustic signatures quite accurately. This holds for the overall sound pressure level in dependence of the emission angle, for sound-pressure level time histories and for one-third-octave spectra.

Descriptors :   *SUBSONIC FLIGHT, *MILITARY AIRCRAFT, *AIRCRAFT ENGINE NOISE, *ACOUSTIC DATA, ACOUSTIC SIGNATURES, ACOUSTICS, AIRCRAFT, ALTITUDE, ANGLES, BROADBAND, EMISSION, FLIGHT, JET AIRCRAFT, MEASUREMENT, MIXING, NOISE, NUMBERS, PREDICTIONS, PRESSURE, SHOCK, SIGNATURES, SOUND, SOUND PRESSURE, TIME, FIXED WING AIRCRAFT.

Subject Categories : Acoustics
      Military Aircraft Operations

Distribution Statement : APPROVED FOR PUBLIC RELEASE