Flow-induced vibrations and damages of hydrofoil systems

Vibrations of hydrofoils on fast ferries are the subject of this paper. Relatively small foil surfaces, already supporting the total ship weight, must sustain unsteady hydrodynamic forces in rough seas and while maneuvering. The resulting hydrofoil oscillations can be estimated for practical purposes, as well as the consequences of such motions. Typical damage induced by vibrations on hydrofoil systems is shown. The eminent example of self-excited oscillations is the hydrofoil singing phenomenon, which is caused by interaction between the foil trailing knife and vortex shedding from the foil trailing edge. Discussion of this effect and means for elimination of the singing phenomenon are presented.