Signifficant decrease in power consumption of wireless devices has been the result of advances in micro/nano technology and fabrication process. However, survivability of such a kind of devices has always been a big concern for engineers. Ambient energy, where the harvested energy is clean and freely available in the device surroundings environment, has been utilized as an alternative solution for powering wireless devices in the past decades. Among diverse kinds of ambient energy, vibration-based harvesting energy has received considerable attention due to potential of low level vibrations occurring in ambient environments including; large commercial buildings, automobiles, trains and industrial environments. This dissertation presents and discusses the experimental and empirical results related to piezoelectric fluidic energy harvesters (PFEH) subjected to vortex induced vibration (VIV). A VIV-based PFEH consists of a light weight rigid circular cylinder mounted on the upstream tip of an elastic cantilever beam which is partially covered by piezoelectric patches. First, the interaction between stationary circular cylinders and laminar fluid flows are discussed. Understanding the stationary cylinder flows might be a key point to determine the VIV dynamic response since cylindrical structures subjected to VIV at pre-lock-in regime are essentially stationary. In addition, a fluidelastic system model is developed to empirically model the VIV dynamic response. The aerodynamic forces are analytically derived and implemented into the model. A robust experimental setup is developed to measure the aerodynamic forces and determine functionality of the aerodynamic forces to the cylinder vibration. Furthermore, effects of finite-length circular cylinders with spanwise free-ends on the VIV dynamic response is demonstrated. In particular, it has experimentally shown that the cylinder aspect-ratio influences not only the amplitude response of the cylinder but also the lock-in regime bandwidth. Finally, some unique opportunities which exist to increase the power harvested with PFEHs by almost an order of magnitude higher than existing methods by exploiting dynamic non-linearity and deploying multi-element arrays in carefully selected positions in a fluid flow field are presented.