Ballistic Wave from Projectiles and Vehicles of Simple Geometry

Varnier, Jean; Pape, Marie-Claire Le; Sourgen, F.

doi:10.2514/1.j056239

Cited by 4 publications

(2 citation statements)

References 42 publications

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“…Solving the weak shock equations (Edwards, 2009; ReVelle, 1976; Silber et al., 2015), with additional calculations based upon Varnier et al. (2018), enables us to estimate the energy dissipated into the atmosphere by the spacecraft's entry with increasing distance from its trajectory line.…”

Section: Methodsmentioning

confidence: 99%

“…The spacecraft is treated as a cylindrical line source, which is justified on the grounds that the opening angle of the Mach cone is small at hypersonic velocities. Solving the weak shock equations (Edwards, 2009;ReVelle, 1976;Silber et al, 2015), with additional calculations based upon Varnier et al (2018), enables us to estimate the energy dissipated into the atmosphere by the spacecraft's entry with increasing distance from its trajectory line.…”

Section: Signal Amplitudesmentioning

confidence: 99%

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Listening for the Landing: Seismic Detections of Perseverance's Arrival at Mars With InSight

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Section: Methodsmentioning

confidence: 99%

Section: Signal Amplitudesmentioning

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Listening for the Landing: Seismic Detections of Perseverance's Arrival at Mars With InSight

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Formation and propagation characteristics of a weak shock wave in maglev tube

Wang,

Xiong,

Wen

et al. 2024

Physics of Fluids

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The propagation of the weak shock wave (WSW) to the tunnel exits and their radiation as micro-pressure waves (MPWs) may cause sonic booms or structural resonance of buildings, posing potential hazards to humans, animals, and buildings in the exit's environment. The characteristics of the WSW and sonic booms of a maglev train/tube coupling model were studied based on the two-dimensional axisymmetric unsteady Reynolds average Navier–Stokes turbulence model. In the later stage of a MPW, the formation mechanism, geometry, and kinematic characteristics of compressible vortex rings (CVRs) were systematically analyzed. The inertial effect causes the initial wavefront to gradually transition from a Gaussian-shape waveform to a triangular waveform during its propagation, eventually coalescing into a WSW. The overpressure, density jump, and shock Mach number at the WSW location all increase with the increasing train speed, while the WSW thickness decreases accordingly. The formation distance of the WSW is inversely proportional to the amplitude of the initial wavefront gradient, and the WSW directly causes the occurrence of the exit sonic boom. The MPW amplitude has significant directionality with a largest value in the axial direction. Within the speed range of 450–700 km/h, the sound pressure level of the MPW exceeds the hearing threshold and even reaches the feeling threshold. The evolution of CVRs includes primary CVR, secondary CVR, and Kelvin–Helmholtz vortices. Primary CVR has the greatest impact on the axial MPW among them. The occurrence of CVRs will cause a second small noise level other than the sonic boom.

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Model calculations and measurements of shooting sound in practical situations

Salomons,

van der Eerden,

van den Berg

2024

The Journal of the Acoustical Society of America

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Shooting sound in practical situations with propagation distances up to 300 m is investigated by means of model calculations and measurements. The results illustrate uncertainties in the model calculations for practical situations. The measurements were performed with various small-caliber weapons. Microphones were placed at positions screened by a noise barrier, and also at unscreened positions. The measured signals contain muzzle sound and bullet sound. The model calculations for muzzle sound and bullet sound take into account emission spectra and various propagation attenuation terms, including ground attenuation and barrier attenuation. The bullet sound model is based on a nonlinear theory of N waves generated by supersonic projectiles. For the unscreened situation, model and measurement results show that the sound levels are considerably reduced by ground attenuation. Ground-level variations and ground roughness in the measurement area play an important role. At a 300 m distance, the A-weighted bullet sound level is higher than the A-weighted muzzle sound level, which underlines the importance of bullet sound. For the screened situation, model and measurement results are used to analyze diffraction of bullet sound by the horizontal and vertical edges of the barrier. The diffraction is explained by considering Fresnel zones on the bullet trajectory.

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Ballistic Wave from Projectiles and Vehicles of Simple Geometry

Cited by 4 publications

References 42 publications

Listening for the Landing: Seismic Detections of Perseverance's Arrival at Mars With InSight

Listening for the Landing: Seismic Detections of Perseverance's Arrival at Mars With InSight

Formation and propagation characteristics of a weak shock wave in maglev tube

Model calculations and measurements of shooting sound in practical situations

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