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Comparisons of two effective medium approaches for predicting sound scattering by periodic arrays of elastic shells (2013)
Journal Article
sound scattering by periodic arrays of elastic shells. ˜The œJournal of the Acoustical Society of America (Online), 134(5), 3619-3630. https://doi.org/10.1121/1.4824340

Two effective medium models are presented and used to predict complex reflection and transmission
coefficients of finite periodic arrays of resonant elastic shells as well as their effective density
and bulk modulus at low frequencies. Comparisons... Read More about Comparisons of two effective medium approaches for predicting sound scattering by periodic arrays of elastic shells.

Analytical approximations for low frequency band gaps in periodic arrays of elastic shells (2013)
Journal Article
in periodic arrays of elastic shells. ˜The œJournal of the Acoustical Society of America (Online), 133(2), https://doi.org/10.1121/1.4773257

This paper presents and compares three analytical methods for calculating low frequency band
gap boundaries in doubly periodic arrays of resonating thin elastic shells. It is shown that both
Foldy-type equations (derived with lattice sum expansions... Read More about Analytical approximations for low frequency band gaps in periodic arrays of elastic shells.

Low frequency sound propagation in activated carbon (2012)
Journal Article
Bechwati, F., Avis, M., Bull, D., Cox, T., Hargreaves, J., Moser, D., …Venegas, R. (2012). Low frequency sound propagation in activated carbon. https://doi.org/10.1121/1.4725761

Activated carbon can adsorb and desorb gas molecules onto and off its surface. Research has examined
whether this sorption affects low frequency sound waves, with pressures typical of audible
sound, interacting with granular activated carbon. Imped... Read More about Low frequency sound propagation in activated carbon.

Acoustical properties of double porosity granular materials (2011)
Journal Article
Venegas, R., & Umnova, O. (2011). Acoustical properties of double porosity granular materials. ˜The œJournal of the Acoustical Society of America (Online), 130(5), 2765-2776. https://doi.org/10.1121/1.3644915

Granular materials have been conventionally used for acoustic treatment due to their sound absorptive
and sound insulating properties. An emerging field is the study of the acoustical properties of
multiscale porous materials. An example of these i... Read More about Acoustical properties of double porosity granular materials.

A relaxation approach for time domain modelling of sound propagation in porous media (2011)
Thesis
Turo, D. A relaxation approach for time domain modelling of sound propagation in porous media. (Thesis). Salford : University of Salford

In the present study a relaxation approach to modelling sound propagation in porous media
has been developed. A frequency domain model has been formulated and is shown to allow
an analytical transformation of the governing equat... Read More about A relaxation approach for time domain modelling of sound propagation in porous media.

Microstructure influence on acoustical properties of multi-scale porous materials (2011)
Thesis
Venegas Castillo, R. Microstructure influence on acoustical properties of multi-scale porous materials. (Thesis). Salford : University of Salford

This thesis investigates the microstructure influence on the acoustical properties of
multi-scale porous materials. The theory of sound propagation in multi-scale materials
is extended to account for physical processes specific to very small pores,... Read More about Microstructure influence on acoustical properties of multi-scale porous materials.

Volumetric diffusers : pseudorandom cylinder arrays on a periodic lattice (2010)
Journal Article
Hughes, R., Angus, J., Cox, T., Umnova, O., Gehring, G., Pogson, M., & Whittaker, D. (2010). Volumetric diffusers : pseudorandom cylinder arrays on a periodic lattice. ˜The œJournal of the Acoustical Society of America (Online), 128(5), 2847-2856. https://doi.org/10.1121/1.3493455

Most conventional diffusers take the form of a surface based treatment, and as a result can only operate in hemispherical space. Placing a diffuser in the volume of a room might provide greater efficiency by allowing scattering into the whole space.... Read More about Volumetric diffusers : pseudorandom cylinder arrays on a periodic lattice.

Predictions and measurements of sound transmission through a periodic array of elastic shells in air (2010)
Journal Article
a periodic array of elastic shells in air. ˜The œJournal of the Acoustical Society of America (Online), 128, 3496. https://doi.org/10.1121/1.3506342

Analytical and numerical approaches have been made to the problems of (a) propagation through a doubly periodic array of elastic shells in air, (b) scattering by a single elastic shell in air, and (c) scattering by a finite periodic array of elastic... Read More about Predictions and measurements of sound transmission through a periodic array of elastic shells in air.

Effect of boundary slip on the acoustical properties of microfibrous materials (2009)
Journal Article
Umnova, O., Tsiklauri, D., & Venegas Castillo, R. (2009). Effect of boundary slip on the acoustical properties of microfibrous materials. ˜The œJournal of the Acoustical Society of America (Online), 126(4), 1850-1861. https://doi.org/10.1121/1.3204087

A variety of new porous materials with unusually small pores have been manufactured in the past decades. To predict their acoustical properties, the conventional models need to be modified. When pore size becomes comparable to the molecular mean free... Read More about Effect of boundary slip on the acoustical properties of microfibrous materials.

Effects of porous covering on sound attenuation by periodic arrays of cylinders. (2006)
Journal Article
Umnova, O., Attenborough, C., & Linton, J. (2006). Effects of porous covering on sound attenuation by periodic arrays of cylinders. ˜The œJournal of the Acoustical Society of America (Online), 119(1), 278-284. https://doi.org/10.1121/1.2133715

The acoustic transmission loss of a finite periodic array of long rigid cylinders, without and with porous absorbent covering, is studied both theoretically and in the laboratory. A multiple scattering model is extended to allow for the covering and... Read More about Effects of porous covering on sound attenuation by periodic arrays of cylinders..

Deduction of tortuosity and porosity from acoustic reflection and transmission measurements on thick samples of rigid-porous materials (2005)
Journal Article
Umnova, O., Attenborough, K., Shin, H., & Cummings, A. (2005). Deduction of tortuosity and porosity from acoustic reflection and transmission measurements on thick samples of rigid-porous materials. Applied Acoustics, 66(6), 607-624. https://doi.org/10.1016/j.apacoust.2004.02.005

An acoustic method for obtaining the tortuosity, and porosity of thick samples of rigid porous materials consisting of large (>1 mm) grains or fibres is proposed. The method uses pulses with central frequencies close to 12 kHz and an approximate... Read More about Deduction of tortuosity and porosity from acoustic reflection and transmission measurements on thick samples of rigid-porous materials.

Response of multiple rigid porous layers to high levels of continuous acoustic excitation (2004)
Journal Article
Umnova, O., Attenborough, K., Shin, H., & Cummings, A. (2004). Response of multiple rigid porous layers to high levels of continuous acoustic excitation. https://doi.org/10.1121/1.1766051

A model has been developed for the response of a rigid-porous hard-backed medium containing an arbitrary number of layers to high amplitude sound. Nonlinearity is introduced by means of a velocity-dependent flow resistivity in Johnson's equivalent fl... Read More about Response of multiple rigid porous layers to high levels of continuous acoustic excitation.

Behavior of rigid – porous layers at high levels of continuous acoustic excitation: Theory and experiment (2003)
Journal Article
Umnova, O., Attenborough, K., Cummings, A., & Standley, E. (2003). Behavior of rigid – porous layers at high levels of continuous acoustic excitation: Theory and experiment. ˜The œJournal of the Acoustical Society of America (Online), 114(3), 1346-1356. https://doi.org/10.1121/1.1603236

A model for the propagation of high amplitude continuous sound through hard-backed rigid-porous layers has been developed which allows for Forchheimer's correction to Darcy's law. The nonlinearity associated with this is shown to be particularly impo... Read More about Behavior of rigid – porous layers at high levels of continuous acoustic excitation: Theory and experiment.

Low frequency sound absorption in a porous material with periodically distributed dead-end pores
Presentation / Conference
Leclaire, P., Umnova, O., Dupont, T., & Panneton, R. Low frequency sound absorption in a porous material with periodically distributed dead-end pores. Presented at EuroNoise 2015, Maastricht, Netherlands

A theoretical and numerical study of the sound propagation in air-saturated porous media with straight pores bearing lateral cavities (dead-ends) is proposed. The straight pores can be considered as the main (Biot) pores. The lateral cavities are loc... Read More about Low frequency sound absorption in a porous material with periodically distributed dead-end pores.