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We prove the unique solvability, passivity/conservativity and some regularity results of two mathematical models for acoustic wave propagation in curved, variable diameter tubular structures of finite length. The first of the models is the generalised Webster’s model that includes dissipation and curvature of the 1D waveguide. The second model is the scattering passive, boundary controlled wave...

[1] Two classes of natural solid media, glacial ice and salt domes, are under consideration as media in which to deploy instruments for detection of neutrinos with energy 10 eV. Though insensitive to 10 to 10 eV neutrinos for which observatories (e.g., AMANDA and IceCube) that utilize optical Cherenkov radiation detectors are designed, radio and acoustic methods are suited for searches for the ...

Research on room acoustic simulation focuses on more accurate modeling of wave effects in rooms. Today, also wave models (e.g., the boundary element method and the finite differences in time domain technique) can be used for higher frequencies, thus, in the geometrical acoustics (GA) domain. Simulations in architectural acoustics are powerful tools but their reliability depends on the input dat...

A spherical acoustic wave is scattered by a bounded obstacle. A generalization of the ‘optical theorem’ (which relates the scattering cross-section to the far-field pattern in the forward direction for an incident plane wave) is proved. For a spherical scatterer, lowfrequency results are obtained by approximating the known exact solution (separation of variables). In particular, a closed-form a...

Numerical simulations are performed to investigate the interaction of acoustic waves with an array of equally-spaced two-dimensional micro-cavities on an otherwise flat plate without external boundary-layer flow. This acoustic scattering problem is important in the design of ultrasonic absorptive coatings (UAC) for hypersonic laminar flow control. The reflection coefficient, characterizing the ...

We present a theoretical and experimental study of the acoustic second-harmonic generation by a single layer of bubbles. This simple system allows us to investigate the subtle interplay between nonlinear effects and multiple scattering. A perturbative model is shown to give an excellent agreement with the experimental measurements, and we demonstrate the existence of an optimal concentration of...

This paper considers acoustic scattering by and propagation through line and plane arrays of air-bubbles in liquid media. The self-consistent method is used to derive the effective scattering function of a single bubble embedded in the arrays, incorporating all multiple scattering processes. For the line case, an exact result is derived. In the plane array situation, only an approximate analyti...