Vibrational Characteristics of A Submerged Double-Shell Structure with Acoustic-Structure Coupling: An Analytical Model and Analysis

The vibrational characteristics in a submerged double-shell structure, which consists of two concentric cylindrical shells coupled by the entrained fluid, are investigated in this paper considering the acoustic-structure coupling. An analytical model is proposed based on the wave propagation approach and the Flügge thin-shell theory, and then a detailed analysis is conducted. The spectrum of the averaged quadratic velocity of total modal superposition is calculated to elucidate the vibrational transmission between inner and outer shells, while that of typical modes are separated to further clarifies the strong and weak coupling. Furthermore, the natural frequencies of the inner and outer shell are determined by the location of the resonance peak in the separated spectrum. The impact of variation of the governing parameters such as the length, the radius and the thickness on the natural frequencies of double-shell structure are investigated and some conclusions are outlined.