An eigenvector method to determine the transient response of cylindrical shells in a fluid with uniform axial flow

A general time domain approach is presented to evaluate the vibratory response of cylindrical shells in time-invariant axial flows to broadband time-dependent excitations. The approach is based on the use of an in vacuo eigenvector expansion with time-dependent coefficients for the velocity field of the shell. A set of convolution integral equations are developed for the eigenvelocities that are coupled due to the fluid loading. These equations are similiar to those developed for planar vibrators and are readily solved by marching forward in time. The known terms in the equations are the ρc fluid-loaded admittances of each eigenvector and the radition impulse responses. Since these are easily obtained, a large number of eigenvectors can be included in the analysis. Numerical results illustrating the responses of a simply supported cylindrical shell to an impulsive ring excitation are presented.