Theoretical and experimental study of a hydro-elastic instability of shaft lines of rotary machines

This research thesis addresses the determination of the effect of the presence of a centrifuged fluid layer (incompressible liquid) with a free surface, in a cylindrical cavity, on the rotor vibratory behaviour. After some generalities on self-excited vibrations and on the stability criterion, a presentation of wave movement in liquid, and of the dynamic of rotors partially filled with liquid (cylinder lateral movement, movement with respect to a stationary point of the cylinder axis), the author reports a theoretical analysis (equations of the movement of a rigid body possessing a cavity containing liquid, study of the stability of a hollow cylinder partially filled of fluid and mounted on a rotating elastic shaft). The last part reports an experimental analysis: description of the experimental installation and measurement devices, study of wave movement (experimental process, interpretation), study of the instability domain (method, interpretation, practical method to get rid of the instability)