Accession Number : ADA301097
Title : Lateral Attenuation of Aircraft Flight Noise.
Descriptive Note : Final rept. Aug 82-Dec 84,
Corporate Author : BBN LABS INC CANOGA PARK CA
Personal Author(s) : Bishop, Dwight E.
PDF Url : ADA301097
Report Date : MAR 1985
Pagination or Media Count : 34
Abstract : This report reviews models for calculating the lateral attenuation of aircraft flight noise, in particular, the change in attenuation for different-elevation angles varying from aircraft directly overhead (900 elevation angle) to a zero elevation angle. Sets of noise spectrum-dependent lateral attenuation values derived from theory and from experimental (AMRL) flight measurements were applied to sets of different aircraft noise spectra to determine A-level differences with elevation angle. The lateral attenuation based on the theoretical model showed near negligible attenuation above 50 elevation angle. The lateral attenuation based on the experimental data showed appreciably greater attenuation, but still less attenuation than the SAE model currently incorporated in the Integrated Noise Model (INM) aircraft noise computer program. Based on the experimental curves, a new generalized transition model was developed and is recommended as a replacement for the current HISEMP lateral transition algorithm. (AN)
Descriptors : *ACOUSTIC ATTENUATION, *AIRCRAFT NOISE, COMPUTER PROGRAMS, MATHEMATICAL MODELS, ALGORITHMS, TURBOFAN ENGINES, TURBOPROP ENGINES, SOUND TRANSMISSION, TAKEOFF, JET FIGHTERS, JET TRANSPORT AIRCRAFT, ELEVATION, RANGE(DISTANCE), FLIGHT PATHS, ACOUSTIC DATA, SOUND PRESSURE, AIRCRAFT LANDINGS, ACOUSTIC IMPEDANCE, ACOUSTIC REFLECTION.
Subject Categories : Acoustics
Attack and Fighter Aircraft
Distribution Statement : APPROVED FOR PUBLIC RELEASE