A laboratory study on the effect of incoming turbulence on the performance of wind turbines

Performance of wind turbines varies significantly with the nature of the incoming flow, especially when under free stream turbulence. Given the complexity of an analytical approach, experimental and computational studies have been undertaken to quantify performance changes. Simplified actuator disk simulations cannot obtain performance figures, and more complicated models are computationally expensive. Experimental studies can measure performance indices, but it is hard to generate consistent free stream turbulence. This study aims to address these problems by experimentally measuring the power and thrust values of a model wind turbine (with a rotor diameter of 180 mm). In order to obtain consistent values of free stream turbulence, an active grid is used to vary the turbulence index from 0 to 10%, with an integral length scale comparable to the rotor diameter. Measurements of generated power are obtained by means of a brushed DC motor, whose angular velocity was varied by changing the electrical load on the poles. Angular velocity, power and their fluctuations have been measured. The turbine was operated in different yawed configurations to examine the effect of wind direction. Hot-wire measurements are also obtained in the wake and the final talk will present results.