Wind energy capture in today’s environment is often focused on producing large amounts of power through massive turbines operating at high wind speeds. The device presented by the authors performs on the extreme opposite scale of these large wind turbines. Utilizing vortex induced vibration combined with developed and demonstrated piezoelectric energy harvesting techniques, the device produces power consistent with peer technologies in the rapidly growing field of micro-energy harvesting. Vortex-induced vibrations in the Karman vortex street are the catalyst for energy production of the device. To optimize power output, resonant frequency of the harvester is matched to vortex shedding frequency at a given wind speed, producing a lock-on effect that results in the greatest amplitude of oscillation. The frequency of oscillation is varied by altering the effective spring constant of the device, thereby allowing for “tuning” of the device to specific wind environments. While localized wind conditions are never able to be predicted with absolute certainty, patterns can be established through thorough data collection. Sampling of local wind conditions led to the design and testing of harvesters operating within a range of wind velocities between approximately 4 mph and 25 mph. For the extremities of this range, devices were constructed with resonant frequencies of approximately 17 and 163 Hz. Frequency variation was achieved through altering the material composition and geometry of the energy harvester. Experimentation was performed on harvesters to determine power output at optimized fluid velocity, as well as above and below. Analysis was also conducted on shedding characteristics of the device over the tested range of wind velocities. Computational modeling of the device is performed and compared to experimentally produced data.
Mixing of Horizontally Injected High-Density Solution in Vertically Upward Low-Velocity Water Flow
