Reradiation of acoustic waves from circumferential waves on elastic shells

Abstract

We consider evacuated thin semi-infinite shells immersed in a fluid, either of cylindrical shape with a hemispherical endcap, or formed two-dimensionally by semi-infinite parallel plates connected by a semi-cylinder. The connected shell portions are joined in a steady fashion although with discontinuous curvature. Acoustic waves are considered axially incident onto the curved portion of the shell, where they, at the critical angle of coincidence, generate Lamb and Stoneley-type waves in the shell. A computer program was written, based on a previous investigation by Cao et al. [Chin. J. Acoust. Soc. Am. 14, 317 (1995)] in order to computationally visualize the waves in the fluid that have been reradiated by the circumferentially propagating shell waves at the critical angle. The results will be used in order to interpret experimental results in which the reradiated waves are optically visualized by the Schardin–Cranz Schlieren method; the latter experimental results will be reported elsewhere.