The Effect of Viscosity on the Dynamics of a Submerged Spherical Shell

In order to clarify the effect of fluid viscosity on the vibrations of submerged elastic shells, the axisymmetric vibrations of a spherical shell immersed in a compressible, viscous fluid medium are studied. The dynamic response of the shell is determined by the classical normal mode method while a boundary layer approximation is employed for the fluid medium. The study of free oscillations reveals that fluid viscosity may produce noticeable effects on the damping components of the complex natural frequencies and is particularly important for the nonradiating modes. For forced vibrations, the present study concluded that the contribution of viscous effect is of small order, except possibly in the vicinity of the peak shell responses when the forcing frequency is near to one of the real components of the natural frequencies.