Iterative approach for optimising coefficient of power, coefficient of lift and drag of wind turbine rotor

This paper presents an approach for the determination of aerodynamic performance characteristics of horizontal-axis wind turbines. The optimum twist of a windmill blade is examined on the basis of elementary blade-element theory. For a given wind speed and blade angular velocity, it is shown that the maximum power efficiency is achieved when the blade is twisted according to a program that depends upon the variation of the sectional lift and drag coefficients with angle of attack. Results for a typical airfoil cross-section show that the optimum angle of attack and optimum twist angle of the blade improves the performance of the wind turbine.