Sound Dissipation by a Small Cylindrical Obstacle

Scattering of a plane wave, obliquely incident on an infinite-elastic conducting solid cylinder, which is freely suspended in a viscous conducting fluid, is considered. The wave motion in both fluid and solid is analyzed into viscous (shear), thermal, and dilatational components. Thus the dissipation, associated with the generation of highly damped viscous and thermal fluid waves at the boundary of the cylinder, is calculated. For a given frequency, this is shown to be a function of the cylindrical harmonic amplitudes of the scattered dilatational wave and of the angle of incidence. Results are presented for the simplified situation of normal incidence and small cylinder radius.