A Numerical Technique for Calculation of the Noise of High-speed Propellers with Advanced Blade GeometryNational Aeronautics and Space Administration, Scientific and Technical Information Office, 1980 - Noise control - 30 pages |
Common terms and phrases
25 30 Harmonic 30 Harmonic number acoustic calculations acoustic formulation acoustic pressure signature acoustic spectrum advanced geometry advanced propellers Aeroacoustics Algorithms angle blade geometry blade surface calculations for SR-1 chord Comparison of experimental computer program conventional propeller curve of intersection curvilinear coordinate data and theoretical dB re 20 Dirac delta function Distance along span divided into panels equation 12 experimental data Experimental O Theoretical function Harmonic number Figure Harmonic number Time/Period helical Mach number helical tip Mach Langley Research Center lift coefficient linear acoustic measured acoustic data method NASA noise calculations noise prediction number Time/Period Figure numerical technique OASPL observer position panels moving parabola pitch change axis planform propeller axis Propeller Noise propellers with advanced radiation vector regula falsi roots of equation scheme sound pressure level source position spectra speed of sound SR-3 blade designs subsonic theoretical calculations tip Mach number transonic undisturbed medium velocity waveforms x3-axis