On the Dynamics of a Rigid Body with Cavities Completely Filled by a Viscous Liquid

This thesis deals with the dynamics of a coupled system comprised of a rigid body containing one or more cavities entirely filled with a viscous liquid. We will present a rigorous mathematical analysis of the motions about a fixed point of this system, with special regard to their asymptotic behavior in time. In the case of inertial motions and motions under the action of gravity, we will show that viscous liquids have a stabilizing effect on the motion of the solid. The long-time behavior of the coupled is characterized by a rigid body motion, and in particular a permanent rotation in the case of inertial motions, and the rest state in the case of a liquid-filled heavy pendulum. Some questions about the attainability and stability of the equilibrium configurations are also answered. Furthermore, we will investigate the time-periodic motions performed by the coupled system liquid-filled rigid body when a time-periodic torque is applied on the solid.