Validation of Aircraft Noise Models at Lower Levels of Exposure

Validation of Aircraft Noise Models at Lower Levels of Exposure

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-07-23

Total Pages: 122

ISBN-13: 9781723481673

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Noise levels around airports and airbases in the United States arc computed via the FAA's Integrated Noise Model (INM) or the Air Force's NOISEMAP (NMAP) program. These models were originally developed for use in the vicinity of airports, at distances which encompass a day night average sound level in decibels (Ldn) of 65 dB or higher. There is increasing interest in aircraft noise at larger distances from the airport. including en-route noise. To evaluate the applicability of INM and NMAP at larger distances, a measurement program was conducted at a major air carrier airport with monitoring sites located in areas exposed to an Ldn of 55 dB and higher. Automated Radar Terminal System (ARTS) radar tracking data were obtained to provide actual flight parameters and positive identification of aircraft. Flight operations were grouped according to aircraft type. stage length, straight versus curved flight tracks, and arrival versus departure. Sound exposure levels (SEL) were computed at monitoring locations, using the INM, and compared with measured values. While individual overflight SEL data was characterized by a high variance, analysis performed on an energy-averaging basis indicates that INM and similar models can be applied to regions exposed to an Ldn of 55 dB with no loss of reliability. Page, Juliet A. and Plotkin, Kenneth J. and Carey, Jeffrey N. and Bradley, Kevin A. Langley Research Center AIRCRAFT NOISE; NOISE INTENSITY; NOISE REDUCTION; FLIGHT CHARACTERISTICS; RADAR TRACKING; POSITION (LOCATION); FLIGHT OPERATIONS; SOUND PROPAGATION; NOISE PREDICTION (AIRCRAFT); AEROACOUSTICS; AUTOMATED RADAR TERMINAL SYSTEM; RELIABILITY; AIRPORTS; APPLICATIONS PROGRAMS (COMPUTERS); EXPOSURE...


Validation of Aircraft Noise Prediction Models at Low Levels of Exposure

Validation of Aircraft Noise Prediction Models at Low Levels of Exposure

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-06-13

Total Pages: 102

ISBN-13: 9781721092222

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Aircraft noise measurements were made at Denver International Airport for a period of four weeks. Detailed operational information was provided by airline operators which enabled noise levels to be predicted using the FAA's Integrated Noise Model. Several thrust prediction techniques were evaluated. Measured sound exposure levels for departure operations were found to be 4 to 10 dB higher than predicted, depending on the thrust prediction technique employed. Differences between measured and predicted levels are shown to be related to atmospheric conditions present at the aircraft altitude. Page, Juliet A. and Hobbs, Christopher M. and Plotkin, Kenneth J. and Stusnick, Eric and Shepherd, Kevin P. (Technical Monitor) Langley Research Center NAS1-20103; RTOP 538-03-15-01


Interior Noise Prediction Methodology

Interior Noise Prediction Methodology

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-07-05

Total Pages: 50

ISBN-13: 9781722316792

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The Acoustical Theory for Design of Aircraft Cabins (ATDAC) is a computer program developed to predict interior noise levels inside aircraft and to evaluate the effects of different aircraft configurations on the aircraft acoustical environment. The primary motivation for development of this program is the special interior noise problems associated with advanced turboprop (ATP) aircraft where there is a tonal, low frequency noise problem. Prediction of interior noise levels requires knowledge of the energy sources, the transmission paths, and the relationship between the energy variable and the sound pressure level. The energy sources include engine noise, both airborne and structure-borne; turbulent boundary layer noise; and interior noise sources such as air conditioner noise and auxiliary power unit noise. Since propeller and engine noise prediction programs are widely available, they are not included in ATDAC. Airborne engine noise from any prediction or measurement may be input to this program. This report describes the theory and equations implemented in the ATDAC program. Mathur, Gopal P. and Gardner, Bryce K. Unspecified Center NAS1-18037; RTOP 535-03-11-03...