The performance coefficient depends on both the pitch angle (β) and the tip speed ratio (λ). The tip speed ratio is calculated by using blade tip speed and wind speed upstream of the rotor.

The relationship between performance coeffi cient (c_p), pitch angle (β) and tip speed ratio (λ) is established by the c_p- λ approximation (3) for different blade pitch angle.-The performance coefficient depends on both the pitch angle (β) and the tip speed ratio (λ). The tip speed ratio is calculated by using blade tip speed and wind speed upstream of the rotor.

The relationship between performance coeffi cient (c_p), pitch angle (β) and tip speed ratio (λ) is established by the c_p- λ approximation (3) for different blade pitch angle.