Acoustics of a moving source in a moving medium with application to propeller noise

Wells, Valana L.; Han, Arris

doi:10.1006/jsvi.1995.0339

Cited by 36 publications

(28 citation statements)

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“…It should be remembered, though, that no set of similarity variables can be of decisive assistance in solving completely a source-modelling problem, for example in determining the sound radiated into a #ow by an oscillating piston [5,11], a pulsating solid sphere [12], a propeller [13}15], or a gust striking an aerofoil [4, 16}18]. Such problems require for their complete solution a #uid-dynamical analysis of the source region and yield only to numerical computation [15] or to advanced mathematical methods, e.g., matched asymptotic expansions [12], blade-number asymptotics [14], and the Wiener}Hopf technique [16], or to special transformations which apply only when M1 [19, 20, 21, section 14.2]. Similarity variables give most complete information about the e!ect of #ow when, as in reference [1], the acoustic source strengths may be regarded as known.…”

Section: Introductionmentioning

confidence: 99%

Similarity Variables for Sound Radiation in a Uniform Flow

Chapman

2000

Journal of Sound and Vibration

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Section: Introductionmentioning

confidence: 99%

Similarity Variables for Sound Radiation in a Uniform Flow

Chapman

2000

Journal of Sound and Vibration

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“…In terms of constitutive models of the material, almost all studies only considered linear elastic and linear viscoelastic materials when tackling dynamics of vehicle-pavement interaction because of the complexity of the problem. Asphalt concrete pavement actually exhibits complex viscoelastic-viscoplastic-damage properties [166][167][168][169][170][171][172], which should be integrated into the subject. Also, it is rare to consider the coupling effect of vehicle-pavement interaction, while this is not the case in train-railway interaction because of the mechanism of the interaction and the relative mass difference between vehicles (e.g., car, truck, train, and airplane) and transportation infrastructure (e.g., highway, bridge, and railway).…”

Section: Discussion and Future Researchmentioning

confidence: 99%

An overview of a unified theory of dynamics of vehicle–pavement interaction under moving and stochastic load

Sun

2013

J. Mod. Transport.

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This article lays out a unified theory for dynamics of vehicle-pavement interaction under moving and stochastic loads. It covers three major aspects of the subject: pavement surface, tire-pavement contact forces, and response of continuum media under moving and stochastic vehicular loads. Under the subject of pavement surface, the spectrum of thermal joints is analyzed using Fourier analysis of periodic function. One-dimensional and two-dimensional random field models of pavement surface are discussed given three different assumptions. Under the subject of tire-pavement contact forces, a vehicle is modeled as a linear system. At a constant speed of travel, random field of pavement surface serves as a stationary stochastic process exciting vehicle vibration, which, in turn, generates contact force at the interface of tire and pavement. The contact forces are analyzed in the time domain and the frequency domains using random vibration theory. It is shown that the contact force can be treated as a nonzero mean stationary process with a normal distribution. Power spectral density of the contact force of a vehicle with walking-beam suspension is simulated as an illustration. Under the subject of response of continuum media under moving and stochastic vehicular loads, both time-domain and frequency-domain analyses are presented for analytic treatment of moving load problem. It is shown that stochastic response of linear continuum media subject to a moving stationary load is a nonstationary process. Such a nonstationary stochastic process can be converted to a stationary stochastic process in a follow-up moving coordinate.

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“…As already mentioned, supersonic jet flows is an area of significant application potential for the Kirchhoff approach. The presented technique may thus be used to derive a formula which contains no Doppler factor, enabling fast prediction of noise in supersonic cases, as depicted by Wells & Han [28]. Another approach without the Doppler factor and its mathematical explanation can be found in [29], leading to formulation 4 of Farassat.…”

Section: Introductionmentioning

confidence: 99%

A time-domain Kirchhoff formula for the convective acoustic wave equation

2016

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Kirchhoff's integral method allows propagated sound to be predicted, based on the pressure and its derivatives in time and space obtained on a data surface located in the linear flow region. Kirchhoff's formula for noise prediction from high-speed rotors and propellers suffers from the limitation of the observer located in uniform flow, thus requiring an extension to arbitrarily moving media. This paper presents a Kirchhoff formulation for moving surfaces in a uniform moving medium of arbitrary configuration. First, the convective wave equation is derived in a moving frame, based on the generalized functions theory. The Kirchhoff formula is then obtained for moving surfaces in the time domain. The formula has a similar form to the Kirchhoff formulation for moving surfaces of Farassat and Myers, with the presence of additional terms owing to the moving medium effect. The equation explicitly accounts for the influence of mean flow and angle of attack on the radiated noise. The formula is verified by analytical cases of a monopole source located in a moving medium.

show abstract

Acoustics of a moving source in a moving medium with application to propeller noise

Cited by 36 publications

References 0 publications

Similarity Variables for Sound Radiation in a Uniform Flow

Similarity Variables for Sound Radiation in a Uniform Flow

An overview of a unified theory of dynamics of vehicle–pavement interaction under moving and stochastic load

A time-domain Kirchhoff formula for the convective acoustic wave equation

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