Analysis of Noise Measured from a Propeller in a WakeNational Aeronautics and Space Administration, Scientific and Technical Information Branch, 1984 - Airplanes - 45 pages |
Common terms and phrases
A-weighted sound level acoustic data acoustic signal airfoil sections analysis angle of attack ARA-D Chord and twist chord thick t/c dB AOASPL downstream Effect of propeller efficiency Figure 12 flow 90 flow O 77 given in figure harmonic analysis Langley Research Center lb t/c lb Thrust maximum value mic 3a Microphone 3c microphone locations NACA 0020 airfoil NACA 16-series sections nacelle NASA Noise measurements noise produced observer location overall sound pressure performance and noise pressure level OASPL produced by propeller propeller blade propeller chord thick propeller diameter propeller disk plane propeller in wake propeller noise propeller performance propeller test stand Pusher Propeller quiet flow facility scaled A-weighted sound shown in figure sound pressure level t/c t/c t/c test conditions trends in AOASPL Twin 1 propeller upstream Inplane 30 value of AOASPL velocity defect region wake 15.0 Twin Wake-producing airfoil سا سلسا