Compressional acoustic waves in structure “Piezocylinder - viscoelastic layer - liquid”

In this paper the characteristics (phase velocity and attenuation coefficient) of compressional acoustic waves propagated in piezoelectric cylinder covered by viscoelastic polymeric layer and immersed into viscous fluid are investigated. It is well known that propagation of such waves can be accompanied by radiation of bulk acoustic wave into liquid contacting with the waveguide. This happens in the case if the phase velocity of the wave in the corresponding structure exceeds the speed of sound in the liquid. Due to this, the attenuation of corresponding waves caused by two reasons: it is the viscosity of the liquid and radiation losses. Our calculations allow us to estimate the contribution of each of these mechanisms into the overall attenuation.