VIVWPGEN (Vortex Induced Vibration Wind Power Generation): A Device to Harvest Wind Energy using Wind Blow Induced Vibration

Abstract

To fulfil the ever increasing energy demand,thus increased fossil fuels consumption globally has been posing the serious concern of global warming and climate change.This has shifted focus of research on renewable, eco-friendly green sources of energies. Geophysical fluid flows (wind/river/ocean) are readily available potential sources of clean, sustainable and renewable energy, worthwhile to meet up to large extent the world energy demand by means ofe.g. wind turbines,hydro turbines, marine turbines and wave energy converters, etc. Since geophysical fluid flows have low energy density, therefore large power generation systems are needed to harness the optimum energy. A device intend to harness the energy from geophysical flows must has high energy density, be robust, be unobtrusive, has low maintenance and has a 10–20 years of operational life.
The energy converter systems using vortex induced vibration can fulfil all these criteria. VIV is the fluid-structure interaction phenomenon in which a non-streamlined body called bluff body, submerged in the flowing fluid causes alternate formation and shedding of vortices behind it downstream the flow. The vortex shedding exert alternating lift force perpendicular to the direction of flow on the body and body sets in oscillatory motion. In general, VIV is destructive to the vibrating structures such as high rise buildings, offshore mechanical and civil structures, and care should be exercised to reduce it by optimum design to prevent failure of the system. However, in energy harvesting using VIV, instead of spoiling vortex shedding, VIVsare exploited to increase the amplitude of vibrations, and this vibrational kinetic energy is converted into electric energy.

Based on the literature and the past research, we did an initial mathematical model calculation to establish feasibility of small scale VIVWPGEN and to predict the effect of various parameters on the performance of its physical prototype.We have built a prototype of VIVWPGEN, and measurement results are compared with mathematical model analysis and conclusions are presented. Additionally examined and explored are the impacts of "lock in" phenomena and the surface geometry of bluff bodies (vibrators) on energy conversion efficiency. In order to achieve the best energy conversion efficiency, the design scalability for various aspect ratios of the VIVWPGEN vibrator is also investigated.