Statistical analysis of sound level predictions in refracting and turbulent atmospheres

Renterghem, Timothy Van; Horoshenkov, Kirill V.; Parry, Jordan A.; Williams, Duncan P.

doi:10.1016/j.apacoust.2021.108426

Cited by 7 publications

(7 citation statements)

References 17 publications

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“…Comparisons of the compound gamma distribution to realistic simulations of sound propagation through the atmosphere, using parabolic equation (PE) methods, demonstrate excellent agreement in a range of scenarios involving turbulent scattering, refraction, and ground reflections [12]. A similar PE study for outdoor sound propagation was also performed recently by Renterghem et al [20], although a direct comparison is not possible because the data were presented as sound levels (logarithms of ζ).…”

Section: Amplitude Modulationmentioning

confidence: 68%

Progress in Modeling the Statistical Distributions of Randomly Scattered Sound

Wilson,

Ostashev,

Ronan

et al. 2024

Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023

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Statistical distributions for the amplitude, intensity, and phase of randomly scattered sound are important in a variety of problems involving noise characterization, detection, communication, beamforming, and remote sensing. This paper discusses some recent progress in modeling the distributions of scattered sound and the situations to which they apply. In particular, several extensions to the gamma distribution are described: the compound gamma for signals that have been scattered with randomly varying strength, the variance gamma for the complex products (covariances and cross spectra) between pairs of sensors, and the compound variance gamma for signals at pairs of sensors with varying scattering strength. Furthermore, a new joint amplitude-phase distribution, termed the phase-modulated Rice, is described, which is appropriate for signals that are scattered by inhomogeneities spanning a broad range of spatial scales as occurs in atmospheric turbulence. This distribution employs the basic (unmodulated) Rice distribution for scattering by relatively small (Fresnel-zone scale) turbulent eddies, while the phase is modulated with a von Mises distribution to represent the impact of relatively strong large-scale turbulence.

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Section: Amplitude Modulationmentioning

confidence: 68%

Progress in Modeling the Statistical Distributions of Randomly Scattered Sound

Wilson,

Ostashev,

Ronan

et al. 2024

Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023

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show abstract

“…As example predictions, two moments were selected with a similar and strong upwardly refracting atmosphere, but with contrasting turbulent strengths. Simulations were performed with the Green's Function Parabolic Equation (GFPE) method, accounting for refraction by an effective sound speed profile and interaction with an acoustically hard ground (rocky terrain) [4]. In Figures 1 and 2, simulation results are shown for a wide range of 1/3 octave bands, both neglecting and correcting for turbulent scattering using the procedure presented in Section 2.…”

Section: Example Calculationmentioning

confidence: 99%

“…Neglecting turbulent scattering in the acoustic shadow zone leads to unrealistic low sound pressure levels, or sound pressure level distributions get extremely long tails [4]. To avoid this, engineering models typically impose a fixed and frequency independent minimum level, relative to free field sound propagation.…”

Section: Introductionmentioning

confidence: 99%

Turbulent scattering in upwardly refracting atmospheres : towards a practical approach

Renterghem

Horoshenkov²

2023

inter noise

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Neglecting turbulent scattering when modelling sound propagation in an upwardly refracting atmosphere leads to unrealistically low levels. Engineering models then typically impose a distance independent constant value for the sound pressure level relative to free field propagation. However, such an approach neglects the strong temporal variability in level one might observe in such an acoustic shadow zone, depending on whether the atmospheric boundary layer is either strongly or weakly scattering. In this work, a modelling framework is presented to account for the effect of such changing scattering contributions, showing that level variations might be as large as 20 dB in such zones. This work contributes to predicting more accurate long-term sound pressure level distributions e.g. near wind turbines.

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“…Existing semi-empirical aircraft noise prediction models use simplified atmospheric conditions to compute sound propagation, neglecting real weather conditions. Nonetheless, several studies by Browne et al [5] and Parry et al [6] have shown, that unsteady propagation effects have a significant impact on ground noise levels and need to be accounted for. Research by Binder [7] has dealt with the meteorological influence on sound propagation from large aircraft at high altitudes.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Impact of Real Atmospheric Conditions on Noise Propagation from Small Aircraft Technologies

Gharbi,

Elsen,

Schady

2024

Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023

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The commercialization of urban air mobility (UAM) is increasingly coming into focus. Their range of operation is often limited by noise restrictions in urban areas. Besides psychoacoustic factors, the noise perception of individual flights on the ground is strongly affected by sound propagation through the atmosphere. Recent work has focused on scenario predictions of ground-perceived noise originating from large aircraft. Current prediction models use standardized atmospheric conditions to calculate sound propagation. Previous research shows that at high flyover altitudes and scenario calculations, neglecting meteorological factors gives accurate results for the noise perception on the ground. However, a single small aircraft flies at low altitudes such that assumptions as the strong damping of high-frequency noise propagating from an aircraft to an observer are no longer applicable. Therefore, this study quantifies the differences between standard atmospheric conditions in comparison to real atmospheric relations for low flyover altitudes. The impact of several meteorological state variables is investigated. The atmospheric sound propagation is performed by a numerical Lagrangian sound particle model comparable to ray tracing. The analysis highlights the limitations of current modeling approaches. Future work could suggest optimizing flight paths for local weather conditions to minimize

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Statistical analysis of sound level predictions in refracting and turbulent atmospheres

Cited by 7 publications

References 17 publications

Progress in Modeling the Statistical Distributions of Randomly Scattered Sound

Progress in Modeling the Statistical Distributions of Randomly Scattered Sound

Turbulent scattering in upwardly refracting atmospheres : towards a practical approach

Investigation of the Impact of Real Atmospheric Conditions on Noise Propagation from Small Aircraft Technologies

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