The V/STOL Rotary Propulsor Noise Prediction Model developed under contract DOT-FA74WA3477 was updated and evaluated. In the first phase, a literatur review was conducted to identify and evaluate high quality noise measurements of propeller, variable pitch fan, fixed pitch fan, helicopter, lift fan, core engine, and jet noise for the preparation of a data base with emphasis on recent measurements of in-flight propulsors. In the second phase, the effects of forward flight on V/STOL propulsor noise were evaluated and the noise prediction model was improved to give better agreement with current measurement. Lastly, the performance of the noise prediction methodology was evaluated by comparison of calculations with measurements of propulsor noise from the data base. Although certain aspects of the measured propulsor noise, such as installation and ground reflection effects, caused discrepancies between measured and calculated levels (the calculations assume uninstalled propulsors under free-field conditions), the general correlation was good. Typical correlation between measured and calculated one-third octave band levels was plus or minus 5 dB and between measured and calculated dB (A), PNL, PNLT, and EPNL was plus or minus 3 dB. (Kursetz)
V/STOL rotary propulsor noise prediction model update and evaluation
Vorbestimmungsmodell und Bewertung der Geraeuschentwicklung bei rotierenden Antrieben von Kurzstart- und Senkrechtstartflugzeugen und Hubschraubern
US Government Reports ; Dez ; 1-233
1979
233 Seiten
Report
English
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