Propagation of propeller tone noise through a fuselage boundary layer

Hanson, D. B.; Magliozzi, B.

doi:10.2514/3.45081

Cited by 36 publications

(33 citation statements)

References 5 publications

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“…This is consistent with other reports in the literature. 6 Figure 8 seems to indicate that the overall SPL decreases from the maximum point in a manner which one would expect from a point source of radiation, that is according to a radial decrement law. This also appears to be the case for the tonal SPL in Figure 9, although less markedly.…”

Section: Sound Pressure Level Contours On Exterior Fuselage Sidewallsmentioning

confidence: 85%

Beech 1900D flight test to characterize propeller noise on the fuselage exterior

Ewing

Kirk

Swearingen³

2001

7th AIAA/CEAS Aeroacoustics Conference and Exhibit

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This report documents a flight test conducted on the experimental Beech 1900D, operated by Raytheon Aircraft. The flight test was conducted primarily to gain insight into the nature of the air-borne fuselage excitation due to the propellers. A secondary goal was to record wing spar vibrations as a measure of the contribution of structure-borne excitations from the wing and power plant to interior noise. A coarse interior noise survey was also conducted in the passenger section of the fuselage. Twenty flush-mounted microphones were attached to the fuselage exterior to monitor the air-borne excitation in the vicinity of the propellers. Four accelerometers recorded the fore and aft wing spar vibrations at the attachment to the fuselage. A reference microphone and a moveable, 8-microphone array were used to record interior noise. Data analysis has revealed that the point of highest sound pressure on the exterior lies forward of the propeller plane during all flight conditions. The magnitude of the excitation tends to decrease in proportion with the inverse of distance from the point of highest sound pressure. The relevance of this observation is that the excitation from a propeller can be very easily modeled in analysis.

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Section: Sound Pressure Level Contours On Exterior Fuselage Sidewallsmentioning

confidence: 85%

Beech 1900D flight test to characterize propeller noise on the fuselage exterior

Ewing

Kirk

Swearingen³

2001

7th AIAA/CEAS Aeroacoustics Conference and Exhibit

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“…The results of these studies revealed a qualitative agreement with the experimental data for acoustic loads on an aircraft fuselage. To improve the quantitative agree ment, solutions were proposed to a three dimensional problem for a monopole noise source [13] and a pro peller [14] near a round hard cylinder, as well as near a hard cylinder with a nonaxisymmetric cross section [15]. The results of three dimensional calculations agreed well with experimental data.…”

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confidence: 76%

The effect of an aircraft’s boundary layer on propeller noise

Belyaev

2012

Acoust. Phys.

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Today, it is greatly hoped that the effect of noise screening with airframe design elements (wing, fuse lage, empennage, etc.) can be used to reduce engine noise. It is expected that this will enable significant reduction in community noise in comparison to tradi tional design. To estimate the size of the screening effect, the simplest model of a point source near a hard surface is commonly used (see, e.g., [1]); the presence of the boundary layer at the surface is usually ignored.This work is devoted to studying how the boundary layer at an aircraft's fuselage affects engine noise. The influence of the boundary layer has been studied mainly in relation to simulation of acoustic loads on the fuselage surface, which are necessary for deter mining noise in an aircraft's cabin (the problem of noise simulation in an aircraft cabin has been eluci dated in [2][3][4]). So, in [5][6][7], the influence of the boundary layer was considered in the simplest case of plane waves and a two dimensional boundary layer on an infinite plane, and it was shown that the boundary layer can exert a significant effect on the acoustic load at the surface of a body. For the two dimensional problem, analytic solutions for noise propagation in an isothermal isentropic boundary layer for three velocity profiles were obtained-linear [8], exponen tial [9], and in the form of a hyperbolic tangent [10]-as well as in a nonisothermal boundary layer with a lin ear velocity profile [11]. A two dimensional problem for a realistic boundary layer velocity profile was numerically solved in [12], where it was found that the boundary layer effect can attain a value of 30 dB. The results of these studies revealed a qualitative agreement with the experimental data for acoustic loads on an aircraft fuselage. To improve the quantitative agree ment, solutions were proposed to a three dimensional problem for a monopole noise source [13] and a pro peller [14] near a round hard cylinder, as well as near a hard cylinder with a nonaxisymmetric cross section [15]. The results of three dimensional calculations agreed well with experimental data.The aim of this work is to determine the boundary layer effect not on acoustic loads at an aircraft's fuse lage, but on community aircraft noise. To the best of the author's knowledge, the only study dealing with this influence is [13], which considered a point mono pole as a noise source. The justification for replacing a distributed noise source with a point source as applied to problems of noise screening with a surface was stud ied in detail in [16] using a propeller as an example, and it was shown that such a replacement can lead to substantial errors, even if the propeller is simulated by several point sources instead of just one. The impor tance of taking into account source distribution in studying noise scattering by a hard surface was also demonstrated for turbulence jet noise in [17] and vor tex wake noise behind a bluff body in [18]. Therefore, it is of interest to study how the boundary layer at the fuselage affect...

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“…A number of analytic methods are available for predicting various 'installation effects'. In particular, the sound pressure on the surface of the fuselage can be predicted using the method proposed by Hanson and Magliozzi (44) . This method models the 'incident' tone noise produced by a propeller using the Hanson's frequency domain radiation formulae.…”

Section: Installation Effectsmentioning

confidence: 99%

Advanced open rotor noise prediction

Kingan

2014

Aeronaut. j. (1968)

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The purpose of this paper is to describe the current status of open rotor noise prediction methods and to highlight future challenges in this area. A number of analytic and numerical methods are described which can be used for predicting 'isolated' and 'installed' open rotor tonal noise. Broadband noise prediction methods are also described and it is noted that further development and validation of the current models is required. The paper concludes with a discussion of the analytical methods which are used to assess the acoustic data collected during the high-speed wind-tunnel testing of a model scale advanced open rotor rig. IntroductIonThe advanced open rotor offers potentially significant reductions in fuel burn relative to current generation turbo-fan engines. Because of this significant benefit, the open rotor is currently being investigated by a number of leading aeronautical companies as a potential aircraft propulsor. A cut-away view of an open rotor concept is shown in Fig. 1 below. The engine consists of two contra-rotating rotors which, in this case, are driven by a gas turbine engine housed within a large centrebody which protrudes both fore and aft of the rotors. In order to be a viable aircraft engine, the open rotor will need to meet stringent noise certification standards and thus, a range of prediction methods are required for assessing the noise produced by various open rotor designs. These range from simple analytical methods, which are useful for design optimisation studies e.g. Parry and Vianello (1) , to high-fidelity CFD/CAA methods which are useful for design validation e.g. Colin et al. (2) . The purpose of this paper is to describe a range of noise prediction methods and, in particular, to highlight recent developments and to identify further work which is required.

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Propagation of propeller tone noise through a fuselage boundary layer

Cited by 36 publications

References 5 publications

Beech 1900D flight test to characterize propeller noise on the fuselage exterior

Beech 1900D flight test to characterize propeller noise on the fuselage exterior

The effect of an aircraft’s boundary layer on propeller noise

Advanced open rotor noise prediction

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