Supersonic Jet Exhaust Noise at High Subsonic Flight Speed PDF Download

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721010196
Category :
Languages : en
Pages : 90

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Book Description
An empirical model to predict the effects of flight on the noise from a supersonic transport is developed. This model is based on an analysis of the exhaust jet noise from high subsonic flights of the F-15 ACTIVE Aircraft. Acoustic comparisons previously attainable only in a wind tunnel were accomplished through the control of both flight operations and exhaust nozzle exit diameter. Independent parametric variations of both flight and exhaust jet Mach numbers at given supersonic nozzle pressure ratios enabled excellent correlations to be made for both jet broadband shock noise and jet mixing noise at flight speeds up to Mach 0.8. Shock noise correlated with flight speed and emission angle through a Doppler factor exponent of about 2.6. Mixing noise at all downstream angles was found to correlate well with a jet relative velocity exponent of about 7.3, with deviations from this behavior only at supersonic eddy convection speeds and at very high flight Mach numbers. The acoustic database from the flight test is also provided.Norum, Thomas D. and Garber, Donald P. and Golub, Robert A. and Santa Maria, Odilyn L. and Orme, John S.Armstrong Flight Research Center; Langley Research CenterJET AIRCRAFT NOISE; JET EXHAUST; SUBSONIC SPEED; SUPERSONIC SPEED; MATHEMATICAL MODELS; AEROACOUSTICS; FLIGHT TESTS; SHOCK WAVES; SUPERSONIC TRANSPORTS; MACH NUMBER; JET MIXING FLOW; F-15 AIRCRAFT; PRESSURE RATIO; EXHAUST NOZZLES; VORTICES; DATA REDUCTION; DATA ACQUISITION