• Wind and Structures
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• v.34 no.4
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• pp.385-394
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• 2022

Global Warming has been driven majorly by the consumption of fossil fuels. Harnessing energy from wind is viable solution towards reducing carbon footprint created due to burning such fuels, However, wind turbines have their problems of flow separation and aerodynamic stall to tackle with. In an attempt to delay the stall angle and improve the aerodynamic characteristics of the NACA 0015 symmetrical aerofoil, lateral cylindrical ridges were attached to its suction surface, at chord positions ranging from 0.1c to 0.5c. The characteristics of the original and ridged aerofoils were obtained using simultaneous pressure readings taken in a wind tunnel, at a free stream Reynolds number of R_e = 2.81 × 10⁵ for a wide range of free stream angles of attack ranging from -45° to 45°. Depending on the ridge size, a delay in stall angle varying from 5° to 20° was achieved together with the maximum increase in lift in the post-stall phases. Additionally, efforts were made to identify the optimum position for each ridge.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.5
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• pp.407-411
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• 2005

A simulation investigation on the circular cylindrical reentrant cavity with axial ridges and a cylindrical circumferential slot is presented. This study indicates that by properly adjusting the dimensions of the ridge sand the slot, the size of the cavity can be miniaturized to around $\lambda_0$ The simulation results using CST MWS show good agreement with past theoretical predictions and provide useful insight into fundamental concerns associated with electrically small antennas.