Thermoviscous effects on acoustic scattering by elastic solid cylinders and spheres

Abstract

This paper presents analytic solutions and numerical results of the scattering of plane sound waves from a thermoelastic circular cylinder and from a thermoelastic sphere in an infinite, thermoviscous fluid medium. The thermoelastic properties of the cylinder and the sphere and the viscosity and thermal conductivity of the surrounding fluid are taken into consideration in the solutions of the acoustic-scattering problems. The associated acoustic quantities, such as the acoustic-radiation force, the acoustic attenuation, and the acoustic-scattering pattern, are first derived in closed forms and then evaluated numerically for a given set of material properties. Numerical results show that increasing fluid viscosity tends to increase the magnitudes of the acoustic-radiation force, the acoustic attenuation, and the angular distribution of the scattering pattern. However, the opposite trends are observed when the fluid temperature increases. The plots of the acoustic attenuation coefficients versus the dimensionless wavenumber of the incident sound wave reveal oscillatory phenomena, which are caused by the resonant vibrations of the cylinder or the sphere.