An aerodynamic measurement system to improve the efficiency of wind turbine rotor blades

The wind energy sector is growing rapidly with the installation of wind turbines with long, slender blades in diverse sites. To enhance operational performance under specific wind conditions and validate the aerodynamic design of flexible blades, comprehensive field aerodynamic data is crucial. However, published field measurements are scarce for large-scale rotor blades due to complex and costly installation of the requisite measurement systems. In recent work, we developed a wireless and self-sufficient aerodynamic measurement system, named Aerosense, which is less complex and costly than conventional aerodynamic measurement systems. The system uses sensors to obtain local aerodynamic pressures, blade motions, and inflow conditions. In this paper, we demonstrate the value of Aerosense in understanding the aerodynamic behaviour of rotor blades, using a 74W wind turbine operating in the field. After a thorough calibration and correction process, we demonstrate, for example, that the pressure distribution can vary significantly during one rotation of the blade, even under stable wind conditions. These variations are found to be due to the misalignment of the wind direction with the wind turbine's rotational axis. We therefore conclude that the developed measurement system is valuable for understanding aerodynamic loading on rotor blades as well as the influence of the inflow conditions on wind turbine performance. This measurement system is applicable to other wind engineering challenges requiring distributed pressure measurements on large or flexible structures, such as bridges, cables, and building façades.