Creeping waves and lateral waves in acoustic scattering by large elastic cylinders
Abstract
The connection between creeping wave and flat surface wave theory was established by investigating the limit of acoustic scattering from a solid elastic cyclinder imbedded in a fluid, whose radius tends to infinity. The asymptotic behavior of the complex circumferential wave numbers was calculated by substituting the appropriate Debye- or Airy-type asymptotic expansions into the 3 x 3 secular determinant and solving it using iterative techniques. The creeping wave modes fall into two classes: (1) those with speeds close to the sound speed in the fluid (Stoneley and Franz waves) and (2) those with speeds close to the bulk wave speeds in the solid (Rayleigh and Whispering Gallery waves). Graphical results are presented for an aluminum cylinder in water for the complex wave number plane, phase velocities, and attenuations, all as functions of fluid wave number times cylinder radius. The results show good agreement with existing numerical results.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- May 1975
- Bibcode:
- 1975PhDT.........9F
- Keywords:
-
- Acoustic Scattering;
- Elastic Cylinders;
- Wave Propagation;
- Asymptotic Methods;
- Transformations (Mathematics);
- Whispering Gallery Modes;
- Acoustics