Sonic boom propagation through a realistic turbulent atmosphere

Boulanger, Patrice; Raspet, Richard; Bass, Henry E.

doi:10.1121/1.413792

Cited by 24 publications

(12 citation statements)

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“…An averaging process then leads to a relation between the rise time and the spectrum of the turbulence. This scattering approach has been refined by Boulanger et al ͑1995͒ who simulated the variability of sonic boom through a first-order Born approximation of the scattering due to randomly distributed Gaussian "turbules" chosen by a Monte Carlo method realizing an atmosphere with a given temperature spectrum. This physical model is based on an earlier work developed by McBride et al ͑1992͒ for scattering of sound by turbulence in a refractive shadow zone.…”

Section: Introductionmentioning

confidence: 99%

Evidence of wave front folding of sonic booms by a laboratory-scale deterministic experiment of shock waves in a heterogeneous medium

Ganjehi

Marchiano

Coulouvrat

et al. 2008

The Journal of the Acoustical Society of America

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The influence of the planetary boundary layer on the sonic boom received at the ground level is known since the 1960s to be of major importance. Sonic boom propagation in a turbulent medium is characterized by an increase of the mean rise time and a huge variability. An experiment is conducted at a 1:100,000 scale in water to investigate ultrasonic shock wave interaction with a single heterogeneity. The experiment shows a very good scaling with sonic boom, concerning the size of the heterogeneities, the wave amplitude, and the rise time of the incident wave. The wave front folding associated with local focusing, and its link to the increase of the rise time, are evidenced by the experiment. The observed amplification of the peak pressure (by a factor up to 2), and increase of the rise time (by up to about one magnitude order), are in qualitative agreement with sonic boom observations. A nonlinear parabolic model is compared favorably to the experiment on axis, though the paraxial approximation turns out less precise off axis. Simulations are finally used to discriminate between nonlinear and linear propagations, showing nonlinearities affect mostly the higher harmonics that are in the audible range for sonic booms.

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Section: Introductionmentioning

confidence: 99%

Evidence of wave front folding of sonic booms by a laboratory-scale deterministic experiment of shock waves in a heterogeneous medium

Ganjehi

Marchiano

Coulouvrat

et al. 2008

The Journal of the Acoustical Society of America

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“…During the past several years, we have been developing the quasi-wavelet (QW) models of the velocity and temperature fluctuations of atmospheric turbulence. These models had their origins in work by McBride et al (1992), deWolf (1993), Boulanger et al (1995), and Goedecke and Auvermann (1997). In such models, turbulence is represented as a collection of self-similar localized structures of many different sizes.…”

Section: Introductionmentioning

confidence: 99%

Quasi-Wavelet Models of Turbulent Temperature Fluctuations

Goedecke

Wilson

Ostashev

2006

Boundary-Layer Meteorol

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Here, we contribute to the continuing development of the quasi-wavelet (QW) model of turbulence that is currently being used in simulations of sound propagation and scattering in the turbulent atmosphere. We show that a QW model of temperature fluctuations exists for any physically reasonable temperature spectrum of isotropic homogeneous turbulence, including the widely used von Kármán spectrum. We derive a simple formula for the QW shape that reproduces a given spectrum exactly in the energy, transition, and inertial subranges. We also show that simple QW shapes can be normalized to yield an analytic expression for a temperature spectrum that is fairly close to any given spectrum. As an example, we match the Gaussian QW model to the von Kármán spectrum as closely as possible, and find remarkably good agreement in all subranges including the dissipation subrange. We also derive formulae for the variance and kurtosis associated with the QW model, and show how the latter depends on the QW packing fraction and size distribution. We also illustrate how the visual appearance of several QW-simulated temperature fluctuation fields depends on the QW packing fraction, size distribution, and kurtosis.

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“…The general technique of representing turbulence in wave scattering calculations as a collection of discrete, eddy-like structures (sometimes called turbules) apparently originates with DeWolfe [5]. More recently, McBride et al [6] used such a representation for scattering of sound above a complex impedance boundary, and Boulanger et al [7] used it to determine turbulence effects on sonic booms. We call the eddy-like structures quasi-wavelets when the ensemble is constructed from a parent function in a systematic, self-similar manner.…”

Section: Introductionmentioning

confidence: 99%