We study the spectral and polarization properties of acoustic waves propagating in nematic liquid-crystalline rubber materials. We apply the viscoelastic theory of nematic elastomers in the low-frequency (hydrodynamic) limit. Dynamic soft elasticity, exhibited by ideal nematic elastomers under certain geometries of shear at low frequencies, leads to anomalous anisotropy of energy transfer and attenuation of transverse waves. The results suggest an application of this class of materials as an acoustic polarizer medium.

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We develop a theory of elastic waves in oriented monodomain nematic elastomers. The effect of soft elasticity, combined with the Leslie-Ericksen version of dissipation function, results in an unusual dispersion and anomalous anisotropy of shear acoustic waves. A characteristic time scale of nematic rotation determines the crossover frequency, below which waves of some polarizations have a very strong attenuation while others experience no dissipation at all. We study the anisotropy of low-frequency Poynting vectors and wave fronts, and discuss a "squeeze" effect of energy transfer nonparallel to the wave vector. Based on these theoretical results, an application, the acoustic polarizer, is proposed.

Several semianalytical approaches are now available for describing diffraction of a plane wave by the 2D (two dimensional) traction free isotropic elastic wedge. In this paper we follow Budaev and Bogy who reformulated the original diffraction problem as a singular integral one. This comprises two algebraic and two singular integral equations. Each integral equation involves two unknowns, a function and a constant. We discuss the underlying integral operators and develop a new semianalytical scheme for solving the integral equations. We investigate the properties of the obtained solution and argue that it is the solution of the original diffraction problem. We describe a comprehensive code verification and validation programme.