Wave Mixing Effects on a Periodically Ribbed Cylindrical Shell

An examination of the response of a periodically ribbed cylindrical shell shows several effects due to the mixing of fast and slow waves on the shell. In wavenumber-frequency space, this mixing manifests itself in the formation of hybrid modes, for example, mixtures of part shear and part flexural vibration. The mixing is strongest when the phase speeds of the different wave types coincide and so reflect the dispersion curves of the flexural Bloch wavenumber. The dispersion curves may be significantly altered by mixing effects, and even for weak wave mixing the polarization of the fast waves can be changed significantly. This effect greatly alters the coupling of the fast waves to an external fluid.