Fluid-Structure Interaction simulation oEnergy harvesting from natural sources using fluid-elastic phenomena is a new focus of engineering fields, those both industrial than to academic. Several studies, conducted in recent times, indicate as scope of vibration-based energy harvesting the power supply of small devices, like micromechanical systems and sensors. This thesis aims to analyze and simulate the Fluid-Structure Interaction of two possible harvester designs based on the Vortex-induced vibrations (VIVs). The interaction between a bluff body without streamline shape and the flow field in which is immersed cause self-excited phenomena, the separation occurs arising excitation forces, the behavior concerns Fluid-Structure Interaction. From a classical engineering point of view, these scenarios are considered as problems that have to predict in order to be avoided.