To speed up the noise prediction of aeroacoustic sources
the retarded-time equation for a subsonic uniformly rotating point source was transformed into a simple and efficient one. A more accurate initial value estimation method based on the piecewise parabolic approximation of the trigonometric function was presented. Moreover
the Newton's method and the Halley's method were applied to solve the reformed retarded-time equation iteratively. The results show that the present initial value estimation method will reduce the computational time by 20%
and the Halley's method behaves better than the Newton's method in computation efficiency and convergence characteristics.
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references
FARASSAT F, SUCCI G P. A review of propeller discrete frequency noise prediction technology with emphasis on two current methods for time domain calculations [J]. Journal of Sound and Vibration, 1980, 71(3): 399-419.
GARRICK I E, WATKINS C E. A theoretical study of the effect of forward speed on the free-space sound-pressure field around propellers, NACA-TR-1198 [R]. Hampton, USA: Langley Research Center, 1954.
BRENTNER K S. Prediction of helicopter rotor discrete frequency noise: a computer program incorporating realistic blade motions and advanced acoustic formulation, NASA-TM-87721 [R]. Hampton, USA: Langley Research Center, 1986.
NYSTROM P A, FARASSAT F. A numerical technique for calculation of the noise of high-speed propellers with advanced blade geometry, NASA-TP-1662 [R]. Hampton, USA: Langley Research Center, 1980.
LYRINTZIS A S. Surface integral methods in computational aeroacoustics-from the(CFD)near-field to the(acoustic)far-field [J]. International Journal of Aeroacoustics, 2003, 2(2): 95-128.
FARASSAT F. Derivation of formulations 1 and 1A of Farassat, NASA/TM-2007-214853 [R]. Hampton, USA: Langley Research Center, 2007.
SONG Chenyao, XU Guohua. Numerical prediction for the acoustic noise of helicopter rotor in forward flight [J]. Technical Acoustics, 2009, 28(2): 157-163.
PRESS W H. Numerical recipes: the art of scientific computing [M]. Cambridge, UK: Cambridge University Press, 2007: 442-463.