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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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In this study, artificial neural networks (ANNs) have been implemented to recover missing data from the particle image velocimetry (PIV), providing quantitative measurements of velocity fields. Due to laser reflection or lower intensity of particles in the interrogation area, the reconstruction of erroneous velocity vectors is required. Therefore, the distribution of time-averaged and normalized flow characteristics around a circular cylinder has been demonstrated as streamwise and cross-stream velocities at Re = 8000. These velocity components have been given for different regions at x/D = 0.5, x/D = 1.25, x/D = 2, and y/D = 0. These stations have been chosen to estimate missing data for near-wake, mid-wake, far-wake, and symmetry regions. The missing data ratios (A*) for 0.5 ≤ x/D ≤ 2 are A* = 3.5%, 7%, and 10%. In addition, these values are A* = 4%, 8%, and 12% for y/D = 0, while A* = 7.5% for the shaded region. The increment of area positively affects the estimation results for near-wake and mid-wake regions. Moreover, the errors tend to decrease by moving away from the body. At y/D = 0, increasing the area negatively influences the prediction of the results. The mean velocity profiles of predicted and experimental data have also been compared. The missing data have been predicted with a maximum percentage error of 3.63% for horizontal stations. As a result, the ANN model has been recommended to reconstruct PIV data. [ABSTRACT FROM AUTHOR]

The installation of photovoltaic (PV) panels on building roofs has seen a significant increase in recent years due to the rising cost of conventional energy sources. This shift towards renewable energy sources has been driven by the urgent need to mitigate the effects of climate change. PV applications is one of the most sustainable and cleanest sources of renewable energy, producing no greenhouse gas emissions during operation. By reducing reliance on fossil fuels, the use of PV panels can help to reduce carbon emissions and lower the overall carbon footprint of buildings. In addition to the environmental benefits, the installation of PV panels can also provide economic benefits, such as reduced energy costs and increased property value. In the past, installations were mostly made in the direction of the south, but now the roofs of the buildings facing west, east, and even north are also considered for PV panel installations. In this study, a grid-connected PV system with an installed power of 148 kWp at the Konya Technical University (KTUN) campus is modeled by PVsyst software. The PV systems' performance on building roofs oriented in different geographical directions (north, south, east, and west) with a 30° fixed tilt angle was investigated. In the modeling, the solar irradiation coming to the surfaces of the PV panels, electricity production values, performance ratios, and their economic feasibility were calculated. The highest effective irradiation value on the panel surface was obtained from the system facing south, found as 1964.4 kWh/m². It is 20.77%, 22.87%, and 73.48% higher than the solar irradiation obtained at -90°, +90°, and 180° azimuth angles, respectively. It is concluded that the electricity generation amounts of PV systems highly depend on the azimuth angle. Similarly, the highest annual electricity production was obtained from the system installed in the 0° azimuth angle found as 254.77 MWh. The annual total electricity generation is 19.66%, 22.55%, and 69.41% higher in systems modeled toward the east, west, and north, respectively. Performance ratio, defined as the ratio of radiation coming to the panel surface and the electricity produced, has relative values between 0.843 and 0.862 for four different azimuth angles. Furthermore, as an economic analysis, the Basic Payback Period (BPP) of the projects was found as 6.92 years, 4.08 years, 4.88 years, and 5.00 years for the systems modeled in the north, south, east, and west directions, respectively. It can be concluded that the most suitable orientation is south, and the other two directions, east, and west, can also be considered feasible. [ABSTRACT FROM AUTHOR]

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]