Acoustic Scattering from a Cylindrical Shell with Double Internal Rigid Plates

The acoustic scattering from an infinite cylindrical shell with double internal rigid plates at normal incidence is studied by theoretical and experimental approaches. The two rigid plates are attached to the shell along lines parallel to the shell axis symmetrically. The dominant feature of frequency-angle spectra is the interference fringes caused by the reflection waves of attachments in the illuminated region and specular reflection. For a cylindrical shell with double internal plates, there may be several attachments in the illuminated region simultaneously. There will be bright spots when two interference fringes caused by two attachments in the illuminated region intersect, while only interference fringes can be observed for one attachment in the illuminated region. Theoretical and experimental results show that the number of attachments in illuminated region can significantly affect the scattering characteristics, and it is a prominent feature to identify the location of internal plates.