Vortex Induced Vibrations (VIV) take place in many engineering structures, for instance tall buildings, slender chimney stacks, flexible structures in petroleum production, long-span bridges, in the tubes of heat exchange devices, or in electric power lines. Generally, VIV are considered an undesirable effect because they may reduce the lifetime of the structure by fatigue loading. However, VIV can also be used to extract energy from the surrounding flow to convert hydrokinetic energy from ocean currents to electricity. The basic idea is to convert part of the kinetic energy of the incoming fluid flow into oscillatory mechanical energy via VIV. In this way, the kinetic energy of the oscillations can be used for practical purposes like, for instance, electricity production using either an electromagnetic, piezoelectric, or electrostatic conversion system.
The objective of this project is to design an experimental model for power extraction via the Vortex-Induced-Vibration (VIV) of circular cylinders in a mass configuration. We will model the system as a simplified two-degrees-of-freedom mechanical system. Then the energy extraction from a VIV mass system will be studied. The study focuses on the relation between the mechanical parameters of the mass system and the efficiency of energy conversion. There are two main questions that we want to answer: