Optimal angle of attack for untwisted blade wind turbine

The numerical simulation of horizontal axis wind turbines (HAWTs) with untwisted blade was performed to determine the optimal angle of attack that produces the highest power output. The numerical solution was carried out by solving conservation equations in a rotating reference frame wherein the blades and grids were fixed in relation to the rotating frame. Computational results of the 12° pitch compare favorably with the field experimental data of The National Renewable Laboratory (USA), for both inviscid and turbulent conditions. Numerical experiments were then conducted by varying the pitch angles and the wind speeds. The power outputs reach maximum at pitch angles: 4.12°, 5.28°, 6.66° and 8.76° for the wind speeds 7.2, 8.0, 9.0 and 10.5 m/s, respectively. The optimal angles of attack were then obtained from the data.