Abstract:
The study is aiming at the effectiveness of the energy harvesting performance in the wake
of various modified bluff bodies through piezoelectric material. These wake dynamics can
be correlated to the behavior of high-rise buildings, automobiles, in air and submerged
bodies in the water. The applications in the energy requirements include the powering of
acoustic sensor, pressure measurement, ultrasonics, and many other industrial
electromechanical systems that autonomously operated through sensors and actuators.
Hence the need for heavy batteries powering these sensor systems and in turn ensuring a
clean environment. Nine modified bluff bodies with 3, 4, and 5 columns of hemispherical
protrusions with 9, 11, and 13mm diameters are arranged over the surface of the cylinders
and have been investigated for the energy harvesting in their wakes with a piezoelectric
membrane. All the bodies are studied at two flow speeds of 0.15m/s and 0.30m/s and
compared them the results of the simple circular cylinder outcomes. The findings showed
that the 4 columns arrangements have shown a greater output power efficiency with a 41%
increase in the power gain following by the 5 column bodies with a 29% increase while the
3 column bodies have shown a power output lagging by about 19%, compared to the simple
cylinder output. The power output is greatly affected by the size and orientation of the
protrusions, the flow speeds, and the streamwise gaps (Gs). Hemispheres with increasing
diameter shown an increasing trend in the power generation. The optimum streamwise gaps
range discovered in this study is 2D ≤ Gs ≤ 3D. The experimentations have been validated
in parallel through the results of the dynamics (frequency and amplitude of oscillations) of
the piezoelectric membrane captured by a camera during the experimentations. Particle
Image Velocimetry (PIV) technique has been used and validated the experimental findings.
