NUMERICAL AND EXPERIMENTAL INVESTIGATION INTO THE EFFECT OF LEADING-EDGE PROTUBERANCES ON THE AERODYNAMIC PERFORMANCE OF WIND TURBINE

Abstract

In this paper, the numerical and experimental analysis of the effect of leading-edge protuberances on the performance of small horizontal axis wind turbines (SHAWT) at low Reynolds number was carried out. The wind turbine blades were designed using the blade element momentum theory (BEMT) with wake rotation. The E216 profile was chosen over other airfoils because, in low Reynolds number flow conditions, it gives a high lift-to-drag ratio. The tubercle shapes employed for the study are slot, triangular, and sinusoidal, and their effects on the performance of wind turbine were compared with baseline turbine as well as among themselves. The flow behavior and the influence of pitch angle on the performance of baseline wind turbine were investigated. The numerical simulations were conducted in ANSYS FLUENT R2021, and the experiments carried out in a low-speed wind tunnel were used to validate the results. The numerical equations were solved using a three-dimensional Reynolds-averaged Navier-Stokes equation with a shear stress turbulence (SST) k-? turbulence model. The output power, torque, and coefficient of power (C<inf>P</inf>) values for the baseline turbine increased up to 25° pitch angle and afterwards, a decline was seen. The optimum tip-speed ratio (TSR) was also investigated and found to be 2.67. The pitch angle 25° provides the greatest improvement among all pitch angles examined for the same blade profile. Hence, for the study of different-shaped tubercles (triangular, sinusoidal, and rectangular slot) pitch angle of 25° was considered. Sinusoidal tubercles show a greater lift-to-drag (C<inf>L</inf> /C<inf>D</inf>) ratio than baseline wind turbines, although there is no substantial difference in C<inf>P</inf>. Furthermore, the C<inf>L</inf> /C<inf>D</inf> for triangular and slotted tubercles is more significant than that of the baseline wind turbine, as is the C<inf>P</inf>. When all three tubercles are compared, the slot has the highest C<inf>P</inf>, while the sinusoidal wind turbine has the highest C<inf>L</inf> /C<inf>D</inf>. © 2025 by Begell House, Inc.