Vibration Analysis of Coupled Concentric Cylindrical Shells in Contact with an Annular Fluid Region

The fluid-structure interaction analysis of the vibratory modal characteristics of a vertical thin-walled cylindrical shell containing water, in an adjacent coaxial region is presented by ANSYS software. The cylindrical shells were modeled by 3D solid shell elements（Solsh190） and the fluid was modeled by 3D fluid elements（Fluid30）. The influence of the fluid viscosity and compressibility are negligible. The natural frequency of cylindrical shell and inner rigid shell separated by the fluid annulus, is obtained by finite element method. The results show that with the decreasing of fluid annulus gap, the natural frequency decreases. When simulation with ANSYS Fluid 30, the fluid annulus gap g≥1.5 mm and the Reynolds number R_k≥1478, the calculation error is less than 20%