Vibration and radiation from capped cylindrical shells in water

Abstract

Extensive experimental results will be presented of the vibration and radiation from shaker-driven, cylindrical shells with enclosed ends. Through the past 3 years, a great deal of knowledge about these shells has been gained through the use of nearfield acoustical holography to probe the vibration and radiation fields. These fields are represented globally over the shell, with the help of color displays, and from these pictures the mechanisms involved in vibration and radiation become apparent. Furthermore, with the help of thin shell theory these results are interpreted so that some generalizations can be made about the physics. The importance of a thorough understanding of the theory of vibration and radiation from an infinite cylindrical shell is demonstrated in comparisons of the dispersion relations to the measured data. Also the spatial filtering effect of the fluid on the modes of vibration is shown. This filtering effect is shown to retain the modal nature of the surface vibration leading to a powerful new approach for modal analysis. Also, the effects of the spherical-like endcaps on the vibration and radiation will be discussed.