The degree of insensitivity to atmospheric turbulence was evaluated for five metrics (A-, B-, E-weighted sound exposure level, Stevens Mark VII Perceived Level, and NASA's Indoor Sonic Boom Annoyance Predictor) that correlate to human annoyance from sonic booms. Eight N-wave shaped sonic booms from NASA's FaINT experiment and five simulated "low-boom" sonic booms were turbulized by Locey's ten atmospheric filter functions. The B-weighted sound exposure level value changed the least due to the turbulence filters for twelve of thirteen booms. This makes it the most turbulence stable metric which may be useful for quiet supersonic aircraft certification.
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http://dx.doi.org/10.1121/1.4986209 | DOI Listing |
J Acoust Soc Am
February 2024
Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Sonic boom propagation over land is being studied to ensure a minimal impact on the population in the event that supersonic flight over land becomes permissible. Sonic boom behavior in and around urban areas is particularly important due to the high density of people residing in cities and the increased probability of impacting large numbers of people if urban areas lie in the flight path. This study models sonic booms around urban canyons using a combined ray tracing/radiosity method.
View Article and Find Full Text PDFJ Acoust Soc Am
November 2023
National Aeronautics and Space Administration (NASA) Langley Research Center, 2 North Dryden Street (Mail Stop 463), Hampton, Virginia 23681, USA.
Sonic booms are often modeled using Burgers equations accounting for dominant propagation effects. Scattering effects of turbulence, however, have not been incorporated into such equations, although these effects are ubiquitous in measured sonic booms. This paper formulates the mean scattering effects, including backscattering, using multiple scattering theory and ensemble averaging.
View Article and Find Full Text PDFJASA Express Lett
May 2023
NASA Langley Research Center, MS463, Hampton, Virginia 23681,
PCBoom propagation simulations of the NASA X-59 low-boom in supersonic cruise were conducted using near-field CFD pressure waveforms as inputs to estimate the noise dose range. Low-booms were propagated through realistic atmospheric profiles from the Climate Forecast System Version 2 across the USA, and loudness statistics of the low-booms are presented. The near-field waveforms correspond to aircraft configurations expected to produce minimum- and maximum-loudness levels on the ground.
View Article and Find Full Text PDFJASA Express Lett
January 2023
Structural Acoustics Branch, NASA Langley Research Center, MS 463, Hampton, Virginia 23681, USA
High-fidelity measurement of sonic boom waveforms requires microphones and data acquisition hardware with flat frequency responses extending below 1 Hz. Hardware limitations can pose challenges meeting these requirements. This letter describes an engineering method involving digital pole-shift filtering that can be used in post-processing to extend effective hardware bandwidth.
View Article and Find Full Text PDFJ Acoust Soc Am
November 2022
Pennsylvania State University, University Park, Pennsylvania 16802, USA.
This study examines the behavior of secondary sonic booms on United States (U.S.) coastlines to have a more complete understanding of the impact of supersonic travel on communities.
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