Vibrational power flow analysis of a submerged viscoelastic cylindrical shell with wave propagation approach

The vibrational power flow in a submerged infinite unconstrained viscoelastic cylindrical shell using wave propagation approach is presented. The harmonic motion of the shell and the pressure field in the fluid is described by Flügge shell theory and Helmholtz equation, respectively. The damping characteristics are considered by complex modulus method. Vibrational power flow inputting into the coupled system and propagating along the shell axial direction are both studied. The numerical results indicate input power flow varies with driving frequency and circumferential mode order, and the viscoelastic damping layer will restrict the exciting force inputting power flow into the shell especially for a thicker damping layer and a higher circumferential mode order. Cut-off frequencies do not exist in viscoelastic shell so that the exciting force can input power flow into the shell at any frequency and for any circumferential mode order. Relative to the nearly linear attenuation form of propagation power flow in elastic shell, propagation power flow in viscoelastic shell is exhibited in exponential attenuation form. Viscoelastic layer will have a good damping effect especially at middle or high frequencies. The conclusion may be valuable to the application of viscoelastic damping material on noise and vibration control of submarines and underwater pipes.