Low-frequency multimode-wave propagation in a cylindrical elastic shell filled with fluid

Normally, the properties of axisymmetric waves propagating through a compressible invisc id fluid-filled cylinder based on various non-dissipative boundary conditions (for instance, liquid cylinder with rigid walls, pressure-release walls, or thin solid walls) are investigated in relatively medium, or high frequencies. This paper focuses on analyzing multimode wave propagations in a fluid-filled cylinder at low frequencies, especially for the first two mode waves. Numerical calculations are used to show the frequency dependence of wavenumber and phase velocity in the two low-frequency modes, it is interesting to find how these two waves vary from a rigid boundary condition to an infinitely flexible boundary condition, how these waves depend upon the relative parameters (e.g. Poisson's ratio, wall thickness, Young's modulus), and their physical explanations. Also, the interaction between the fluid and the structure related to the radial wavenumber is investigated for the first mode wave in a fluid-filled cylinder between the two extreme boundary conditions including the rigid and infinite flexible walls.