The dynamic response of a small horizontal-axis wind turbine blade operating in highly turbulent flow

Small horizontal axis wind turbines are generally located close to their load and therefore likely to operate in highly turbulent flows. Operating in highly turbulent flow will lead to increased fatigue loading on all components of the turbine especially the blades. A 2.5m long composite-constructed blade on an Aerogenesis 5kW horizontal-axis wind turbine has been instrumented with 12 strain gauges to measure its response during operation. Signal from these gauges were acquired and transmitted to a stationary computer using V-link LXRS telemetry system. Simultaneous with these measurements signals were acquired that represented turbine rotational speed, turbine yaw and yaw rate, and wind speed and direction. Measurements show the level of strain experience by the blade increased with wind speed and blade rotational speed. At relatively low wind speed, the operating turbine closely tracked the wind direction, however, at higher wind speeds the turbine operated at a significant yaw error. Most gauges recorded significant azimuthal variation in strain even during periods of constant blade rotational speed and wind speed