Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: Numerical Study of Vortex Induced Vibration of various Bluff Bodies for Design Optimization of a Energy Harvester
by Md. Rejaul Haque and M Arshad Zahangir Chowdhury

Abstract:
Flow induced vibration is numerically investigated for flow over three differently shaped bluff-bodies at different fluid velocities to assess the potential of the phenomenon for energy harvesting. The present paper aims to find the most appropriate energy harvester shape as lock in frequency in energy harvesting principle largely depends on bluff body�s structure. To optimize and refine the design of a cantilever based novel energy harvester, the computation has been done for cylindrical, triangular and elliptical bluff bodies to which the harvester is attached. As fluid flows over the structure, the frequency of vibration of the body is estimated at various fluid velocities (Reynolds Number). A Fast Fourier Transformation is performed to yield the frequency of vortex shedding. From the wake velocity profile, lift oscillation and frequency of vortex shedding is estimated. Strouhal numbers of the stated bodies are analyzed. A higher synchronized bandwidth of shedding frequencies is an indication of an optimized harvester design at different Reynolds number and both triangular along with elliptical shaped bluff bodies are more suitable than that of cylindrical shaped bluff bodies. Elliptical shaped bluff bodies yield a wide range of lock-in frequency compared to that of triangular shaped bluff bodies. Finally, the research clearly stated that, bluff bodies shape has a prominent influence on vortex induced vibration and elliptical bluff body gives the highest vibration or energy under stated conditions.

Keywords: CFD, energy harvester, vortex induced vibration (VIV), bluff body, strouhal number

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