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In the present study, active and passive flow control methods have been implemented to investigate their effects on the wake flow structures of a circular cylinder. Grooves having circular, rectangular, and triangular cross sections have been applied to the cylinders exposed to the rotation rates, α, from 0 to 0.79. The experiments have been conducted by particle image velocimetry at a Reynolds number of Re = 5 × 103. The contour graphics of time-averaged results have been presented. Moreover, the variations in velocity profiles have also been depicted. The experimental results revealed significant variations for flow patterns, wake structures, and turbulence parameters due to the effects of both groove geometries and rotational motion. In the stationary cases, for turbulence intensity, the circular grooved cylinder exhibited a 15% increase, while the triangular grooved cylinder showed a slightly higher increase of around 20% compared to that of the bare cylinder (BC). Conversely, in non-stationary cases, the rectangular grooved cylinder displayed the most prominent reduction in turbulence intensity, decreasing by approximately 10% compared to that of the BC. The groove type has considerably affected the flow structures of the wake regions, especially for the lower rotation rates. [ABSTRACT FROM AUTHOR]

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This study modeled monocrystalline (mono-Si), polycrystalline (poly-Si), and amorphous silicon (a-Si) Photovoltaic (PV) systems with a 300 kWp installed power using PVsyst software in Konya province, Turkey. The system's electricity generation was calculated and compared with different PV technologies. In addition, an economic analysis for a 25 year lifespan was made with the obtained data. The annual global horizontal radiation (GI) and effective global irradiation (GE) are found to be 2001.7 kWh/m² and 1949.6 kWh/m², respectively. The highest yearly total electricity production was obtained from mono-Si, with a value of 513.91 MWh. This value is 1.91% and 3.07% higher than poly-Si and a-Si, respectively. Since the Performance Ratio (PR) values are proportional to the generated electricity and incoming irradiation to the surface of the PV panels, it calculated 0.853, 0.847, and 0.830 for mono-Si, poly-Si, and a-Si, respectively. According to the basic payback method, the economic analysis showed that mono-Si and poly-Si pay off in about 5.8-5.9 years, while a-Si pays off in 9,1 years. A net profit of $1.5 million, $1.45 million, and $1.1 million was obtained from mono-Si, poly-Si, and a-Si, respectively. It was concluded that the ratio of income values to investment cost was 253%, 244.77%, and 126.6%, respectively. Therefore, it was concluded that mono-Si and poly-Si are economically quite feasible for small and medium-scale PV systems, but a-Si is still not feasible due to lower efficiency and higher costs. [ABSTRACT FROM AUTHOR]