methods¶

pyNA is developed based on the 1982 theoretical manuals from the Aircraft NOise Prediction Program (ANOPP) by Zorumski [Zorumski-1982]. The following methods from literature are used in the different pyNA modules:

noise source modules¶

Noise source module	Method
Fan broadband and tones (inlet and discharge)	Heidmann method NASA TM X-71763 [Heidman-1975]; with GEAE revision NASA CR-195480 for BB [Kontos-1996a], with AlliedSignal revision for RS tones [Hough-1996], with fan treatment NASA CR-202309 [Kontos-1996b].
Combustor	Emmerling method FAA-RD-74-125 [Emmerling-1976].
Jet mixing	Single-stream, shock-free, circular jet mixing noise [SAE-2012].
Jet shock	Single-stream, circular jet shock cell noise (SAE ARP876-2012).
Airframe	Fink method FAA RD-77-29 [Fink-1977]; with HSR calibration NASA CR-2004-213014 [Rawls-2004].

noise propagation modules¶

Noise propagation module	Method
Spherical spreading	R-squared law
Characteristic impedance effect	Characteristic impedance ratio.
Atmospheric absorption	Exponential decay from source based on absorption coefficient.
Ground reflection and attenuation	Chien-Soroka method [Chien-1975].
Lateral attenuation and engine installation	Berton method [Berton-2021].
Wing shielding module	Maekawa method [Maekawa-1968].

noise levels modules¶

Noise level module	Method
Perceived noise level, tone corrected (PNLT)	ICAO Annex 16 Volume I: Aircraft noise App. 2-13 [ICAO-2017].
Effective perceived noise level (EPNL)	ICAO Annex 16 Volume I: Aircraft noise App. 2-13 [ICAO-2017].

References¶

Heidman-1975: Heidmann, M.F., Interim prediction method for fan and compressor source noise (NASA-TM-X71763), 1975.
Kontos-1996a: Kontos, K.B., Janardan,B., and Gliebe,P., Improved NASA-ANOPP noise prediction computer code for advanced subsonic propulsion systems. Volume 1: ANOPP Evaluation and Fan Noise Model Improvement (NASA CR-195480), 1996.
Hough-1996: Hough, J.W., and Weir, D.S., Aircraft noise prediction program (ANOPP) fan noise prediction for small engines (NASA-CR- 198300), 1996.
Kontos-1996b: Kontos, K. B., Kraft, R. E., and Gliebe, P. R., Improved NASA-ANOPP Noise Prediction Computer Code for Advanced Subsonic Propulsion Systems. Volume 2: Fan Suppression Model Development (NASA-CR-202309), 1996.
Emmerling-1976: Emmerling, J., Kazin, S., and Matta, R., Core Engine Noise Program. Volume III. Prediction Methods–Supplement I.-Extension of Prediction Methods, Tech. rep., General Electric Co Cincinnati OH Aircraft Engine Business Group, 1976.
SAE-2012: Society of Automotive Engineers, ARP-876: Gas Turbine Jet Exhaust Noise Prediction, SAE, 1994.
Fink-1977: Fink, M.R., Airframe noise prediction method, Technical report, United Technologies Research Center East Hartford, CT, 1977.
Rawls-2004: Rawls, J.W., Yeager, J.C., High Speed Research Noise Prediction Code (HSRNOISE) User’s and Theoretical Manual (NASA CR-2004-213014), 2004.
Chien-1975: Chien, C., and Soroka, W., Sound propagation along an impedance plane, Journal of Sound and Vibration, Vol.43, No.1, 1975, pp. 9–20.
Maekawa-1968: Maekawa, Z., Noise reduction by screens, Applied Acoustics, Vol.1, No.3, 1968, pp.157–173.
ICAO-2017(1,2): Annex 16 to the Convention on International Civil Aviation Environmental Protection Volume I: Aircraft Noise*, (2017).
Zorumski-1982: Zorumski, William E. Aircraft noise prediction program theoretical manual, part 1-2., (1982).
Berton-2021: Berton. Simultaneous use of Ground Reflection and Lateral Attenuation Noise Models. (2021).