Experimental measurements of acoustical properties of snow and inverse characterization of its geometrical parameters

Datt, Prem; Kapil, J.C.; Kumar, Ashavani; Srivastava, P. K.

doi:10.1016/j.apacoust.2015.07.015

Cited by 15 publications

(6 citation statements)

References 37 publications

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“…For high porosity snow (φ > 0.8), they report tortuosities of 1.36-1.56 that are higher than our determinations of 1.07-1.27, and their pore wave speeds would be lower. Datt et al (2016) also reported on impedance tube measurements over a higher frequency range from 63 to 6,300 Hz. Their samples were generally lower porosity (with one exception) but most of their tortuosities were near 1.0, with two samples at 1.2 and 1.7.…”

Section: Ultrasonic Wave Determination Of Porosity and Tortuositymentioning

confidence: 98%

Using Ultrasonic Waves to Determine the Microstructure of Snow

et al. 2020

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Acoustic signals interact with the physical structure of porous media, are particularly sensitive to porosity and tortuosity, and can be used to measure physical properties in a non-destructive manner. Given the fragile nature of freshly fallen snow, non-contact, non-destructive characterization methods made possible via acoustic signals, are desirable. High frequency wave propagation methods can be used to determine in-situ, near-surface, micro-pore geometry parameters in snow using methods demonstrated on cohesive porous materials, including manufactured foams, porous metals, and sintered glass beads. High frequency (90 kHz), oblique-angle and near vertical reflection measurements were conducted on snow samples in a cold room to demonstrate the feasibility of acoustic characterization. A nonlinear least squares regression to the theoretical reflection response was used to derive the best-fitting values for the porosity and tortuosity. We compared the acoustically-derived snow physical parameters, including porosity and tortuosity, with values determined from X-ray micro-computed tomography (µCT) for different snow types. The µCT-measured and acoustically-derived methods demonstrated strong agreement for porosity with differences averaging 8% for all samples. Tortuosity values, however, had average differences of roughly 20% for all samples. The different error rates might be caused by the stronger dependence of the acoustic reflection on porosity than on tortuosity. For both parameters, the small grain snow and large grain firn samples had errors much larger than the fresh or 1 day samples. Fresh snow has the lowest reflection coefficients and demonstrates a steady decrease from <0.1 at normal incidence as the angle increases. Aging fresh snow for 1 day caused detectable changes in acoustic response, from slight decreases in porosity, and slight increases in tortuosity that occurred from sintering.

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Section: Ultrasonic Wave Determination Of Porosity and Tortuositymentioning

confidence: 98%

Using Ultrasonic Waves to Determine the Microstructure of Snow

et al. 2020

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“…Several techniques can be used to measure ground impedance (Albert, 2001; ANSI/ASA, 2010; Datt et al, 2016;Guillaume et al, 2015;Moore et al, 1991;Nordtest, 1999). In the present study, the snow impedance was measured in situ using the method proposed by Guillaume et al (2015), which is suited for grazing angles and has been shown to provide reliable data for long-range propagation computation (Dragna et al, 2014).…”

Section: Snow Impedancementioning

confidence: 99%

“…The acoustic properties of the snow cover are identical in all configurations. They are chosen as e ¼ 0:15 m; R s ¼ 20 000 Pa Á s Á m À2 ; X ¼ 0:6; q 2 ¼ 1:66 to be representative of a moderately compacted snow as measured by Datt et al (2016). The meteorological conditions are imposed using wind speed and temperature profiles from MOST (see Sec.…”

Section: A Descriptionmentioning

confidence: 99%

Influence of meteorological conditions and topography on the active space of mountain birds assessed by a wave-based sound propagation model

Guibard

Sèbe

Dragna

et al. 2022

The Journal of the Acoustical Society of America

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The active space is a central bioacoustic concept to understand communication networks and animal behavior. Propagation of biological acoustic signals has often been studied in homogeneous environments using an idealized circular active space representation, but few studies have assessed the variations of the active space due to environment heterogeneities and transmitter position. To study these variations for mountain birds like the rock ptarmigan, we developed a sound propagation model based on the parabolic equation method that accounts for the topography, the ground effects, and the meteorological conditions. The comparison of numerical simulations with measurements performed during an experimental campaign in the French Alps confirms the capacity of the model to accurately predict sound levels. We then use this model to show how mountain conditions affect surface and shape of active spaces, with topography being the most significant factor. Our data reveal that singing during display flights is a good strategy to adopt for a transmitter to expand its active space in such an environment. Overall, our study brings new perspectives to investigate the spatiotemporal dynamics of communication networks.

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“…The experimental apparatus includes long rigid metallic tube, microphones, Gaussian white noise source, variable gain power amplifier, speaker and data acquisition system. The working principle of the impedance tube is based on transfer function method 25 . The acoustic measurements were carried out in 30 mm tube made of heavy steel frame to minimise the vibrations.…”

Section: Investigationmentioning

confidence: 99%

Utilisation of High Energy Propellant Waste in Manufacturing of Fired Clay Bricks to Enhance the Acoustic Properties

Mehta¹,

Kumaraswamy²,

Saraswat³

et al. 2021

Def. Sc. J.

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The disposal and waste management of solid high energy propellant (HEP) is a considerate conservational problem. HEP waste is currently disposed in open or confined burning which may cause environmental hazards. In this paper, we examined and discussed results on recycling of HEP waste into fired clay bricks baked in different orientation. HEP modified bricks with 1.5%, 3% and 5 wt. % HEP waste content were manufactured and tested, and then compared against virgin clay bricks without HEP content. The effect of directional orientation of bricks baked with varying HEP content on acoustic properties were experimented and discussed. The sound transmission loss decreases with increase in HEP waste due to formation of independently closed directional pores. The transmission loss of horizontally baked during firing of bricks is nearly 5dB lower than vertically baked bricks. Results of the experimental studies indicate that HEP waste can be utilised in fired clay bricks and different orientation baking further enhances the acoustic properties.

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Experimental measurements of acoustical properties of snow and inverse characterization of its geometrical parameters

Cited by 15 publications

References 37 publications

Using Ultrasonic Waves to Determine the Microstructure of Snow

Using Ultrasonic Waves to Determine the Microstructure of Snow

Influence of meteorological conditions and topography on the active space of mountain birds assessed by a wave-based sound propagation model

Utilisation of High Energy Propellant Waste in Manufacturing of Fired Clay Bricks to Enhance the Acoustic Properties

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