In this paper, the free vibration characteristics of a half liquid-filled and submerged, horizontal cylindrical shell are investigated with the consideration of the linear sloshing effect by an analytical method. It is assumed that the shell is submerged in water and the shell's equations of motion are described using the Flügge thin shell theory. The internal fluid is partially filled and the free surface wave is taken into consideration in the coupled model. It is assumed that the internal and external fluid is incompressible and inviscid, and the motion of the fluid is described by the Laplace equation. The velocity potential function is introduced to express the fluid. The kinetic and potential energies of the internal liquid are evaluated to obtain the influence of surface oscillation on the fluid-structural coupling vibration. By using the Rayleigh quotient method, the coupled natural frequencies of the shell are obtained. The accuracy of the present method is verified by comparison with published results.
Thin-walled cylinders are widely used in many advanced applications for their excellent static and dynamic performance. And the study of the fluid-shell interaction is of great interest in many fields of engineering, such as aerospace, marine, petrochemical, civil engineering, and so on.
There are many works concerning the vibration of cylindrical shells coupled with surrounding fluid. Zhang et al. (2002) analyzed the natural frequencies of finite cylindrical shells submerged in a dense acoustic medium by using the wave propagation method. Guo et al. (2017) examined the vibration response of the submerged cylindrical shell by using an analytical method. Based on the vibration responses of the shell, the far-field sound pressure is computed by using the boundary element method. Some studies focused on the vibration of shells partially coupled with fluid, where the effect of the free surface exists and should be considered. Amabili (1996) investigated the vibration characteristics of partially-filled cylindrical shells by using the Rayleigh quotation method. Ergin et al. (2002) studied the free vibration characteristics of a partially-filled and submerged cylindrical shell without considering the sloshing effects of the free surface. Lakis et al. (2009) presented a semi-analytical approach to the dynamic analysis of a fluid -filled horizontal cylindrical shell taking into account free surface motion.