Abstract
Selection of airfoil is crucial for better aerodynamic performance and design of aerodynamic applications such as wind turbine and aircrafts. In this paper, a high-lift and low-Reynolds number airfoil has been selected and investigated through computational analysis for applying it for small-sized wind turbines as blades. The S1223 airfoil, designed by the University of Illinois at Urbana-Champaign, was chosen for its high-lift characteristics at low Reynolds number typically encountered by the small wind turbines. CFD work is performed with S1223 airfoil profile over a wide range of conditions of interest to analyze the performance of the airfoil using the Spalart-Allmaras turbulence model.
The results obtained from the simulation works have been compared with experimental data for validation purpose. It has been found that the Spalart-Allmaras model conforms well with the experimental results, though the values of lift coefficients (CI) are slightly less than the experimental results. In the present analysis, velocity distributions are analyzed at different angle of attacks for different turbulence intensities. It has been observed that there is vortex shedding around the trailing edge of the airfoil for both turbulence levels. It has been observed in the present study that due to increase in turbulence intensity, both the maximum lift coefficient and the stall angle increases significantly. It has been found after investigating the effect of turbulence intensity over lift-to-drag coefficient ratio that it drastically decreases due to increase in turbulence intensity up to certain value (about 3.5%), then it starts decreasing in gradual manner.