Suggestions for improving the efficiency and life expectancy of wind turbine blades are proposed in this paper. A new airfoil shape with wide leading edge nose and large camber has been investigated by numerical simulation with a range of attack angles. The results show that the lift-drag ratio of the airfoil is greater than that of the conventional airfoil at large attack angles (α>20°). Changing the local roughness on blade surfaces to improve the wind turbine performance is discussed in the paper. A new mechanism and method of analysing life expectancy of a blade with flow induced vibration in oscillating flow has been given. It is proved that the damping of blade material and structure has great influence on the endurance lifetime of blades. The investigation indicates further that the equilibrium amplitude of vibration greatly influences the lifetime of blades. Changing the damping characteristic of a blade may significantly vary its equilibrium amplitude, so extending the life expectancy of blades. This paper provides the foundations for further study.

Optimum aerodynamic performance of a wind turbine blade demands that the angle of attack of the relative wind on the blade remains at its optimum value. For turbines operating at constant speed, a change in wind speed causes the angle of attack to change immediately and the aerodynamic performance to decrease. Even with variable speed rotors, intrinsic time delays and inertia have similar effects. Improving the efficiency of wind turbines under variable operating conditions is one of the most important areas of research in wind power technology. This paper presents findings of an experimental study in which an oscillating air jet located at the leading edge of the suction surface of an aerofoil was used to improve the aerodynamic performance. The mean air-mass flowing through the jet during each sinusoidal period of oscillation equalled zero; i.e. the jet both blew and sucked. Experiments investigated the effects of the frequency, momentum and location of the jet stream, and the profile of the turbine blade. The study shows significant increase in the lift coefficient, especially in the stall region, under certain conditions. These findings may have important implications for wind turbine technology.