Results 201 to 210 of about 1,176,775 (247)
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An Investigation of Impulsive Rotor Noise Using a Model Rotor
Proceedings of the Symposium on Status of Testing and Modeling Techniques for V/STOL Aircraft, Philadelphia 1972, 1972The investigation of gust induced impulsive rotor noise was made using a 3 bladed 9ft. diameter model rotor. The gust was produced by a series of air-jets placed under the rotor disc and the noise characteristics were determined for a range of gust lengths and amplitudes. The main emphasis was placed on experimental measurements and.
John Leverton, Colin Amor
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Journal of Fluid Mechanics
This study investigates noise generation from co-rotating rotors arranged in a side-by-side configuration. The analysis examines the effects of different phase delays and separation distances. A simple mathematical model is developed to provide insight into constructive and destructive noise interference.
Tiziano Pagliaroli +4 more
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This study investigates noise generation from co-rotating rotors arranged in a side-by-side configuration. The analysis examines the effects of different phase delays and separation distances. A simple mathematical model is developed to provide insight into constructive and destructive noise interference.
Tiziano Pagliaroli +4 more
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Open Rotor Broadband Interaction Noise
18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference), 2012A theoretical model is presented for calculating the broadband noise produced by the interaction of an open rotor with the wake from either an upstream contra-rotating rotor or a stationary pylon. The model is used to investigate the dependence of the radiated noise on parameters such as pylon–rotor gap and the polar and azimuthal directivity of the ...
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10th Aeroacoustics Conference, 1986
A study was made of helicopter tail rotor noise, particularly that due to interactions with the main rotor tip vortices, and with the fuselage separation mean wake. The tail rotor blade-main rotor tip vortex interaction is modelled as an airfoil of infinite span cutting through a moving vortex.
S.-T. CHOU, A. GEORGE
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A study was made of helicopter tail rotor noise, particularly that due to interactions with the main rotor tip vortices, and with the fuselage separation mean wake. The tail rotor blade-main rotor tip vortex interaction is modelled as an airfoil of infinite span cutting through a moving vortex.
S.-T. CHOU, A. GEORGE
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The Journal of the Acoustical Society of America, 1974
The present contribution is concerned with aerodynamic noise from isolated, subsonic tip rotors. With large axial spacing between blade rows and elimination of inlet guide vanes, at least the forward radiated noise from modern single-stage acre-engine fans is dominated by isolated rotor noise.
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The present contribution is concerned with aerodynamic noise from isolated, subsonic tip rotors. With large axial spacing between blade rows and elimination of inlet guide vanes, at least the forward radiated noise from modern single-stage acre-engine fans is dominated by isolated rotor noise.
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Rotational Noise of Helicopter Rotors
The Journal of the Acoustical Society of America, 1965An analysis procedure has been developed to predict propeller rotational noise during nonuniform, as well as uniform, inflow conditions. Although many studies have been conducted since the development of Gutin's equations (NACA TM I195), none have been developed that adequately describe the near and far rotational-noise fields of a helicopter rotor ...
Robert King, Ronald G. Schlegel
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The calculation of transonic rotor noise
AIAA Journal, 1984It is pointed out that an accurate prediction of the high-speed impulsive rotor noise is very difficult since the noise field depends on many complex factors. Schmitz and Yu (1981) have conducted a study with the aim to include local aerodynamic nonlinearities in a calculation regarding the acoustic shock.
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A Parametric Investigation of Rotor-Rotor Interaction Noise Generation
Proceedings of the Vertical Flight Society 79th Annual Forum and Technology Display, 2023Robert Rau, Eric Greenwood
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Mutual Interaction Noise in Rotor-Beam Configuration
30th AIAA/CEAS Aeroacoustics Conference (2024)In small-sized unmanned air vehicle (UAV) configurations, rotor–beam interaction noise is an important contributor to the tonal noise. The emergence of harmonics is enhanced by the presence of the beam in the very near wake downstream of the rotor. Distinct and coupled noise source mechanisms occur.
Emma Vella +5 more
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Experimental study on noise reduction of multi-rotor by phase synchronization
Journal of Sound and Vibration, 2022Mengxue Shao, Xice Xu, Jiaxin Lu
exaly