Characterization of a Fast Response Probe for Inflow Turbulence Measurements on Wind Turbine Blades

Abstract

The performance of a wind turbine, its aerodynamic and acoustic predictions, and expected power output are affected by atmospheric turbulence. Previous studies showed that the installation of high-frequency measurement devices on blades is needed in order to analyze the effect of the inflow turbulence on boundary layer transition and on noise emissions. Therefore, the accuracy of a novel 5-hole high-frequency pitot tube designed to measure high-frequency velocity fluctuations is assessed by testing its capability to determine flow angles and velocity components in a well-defined wind tunnel setup. Moreover, the vortex shedding frequency and magnitude for the flow behind a cylinder and wire are analyzed to evaluate its performance for various turbulent flow scenarios. It is seen that the flow angles and the velocity components can accurately be calculated. The peaks observed in the spectra sampled at high frequencies that are relevant for boundary layer analysis demonstrate the characteristics of the flow with high turbulence intensity values. As the probe is validated for inflow turbulence measurements, it will be used on a wind turbine blade to identify the relevant frequencies that are induced by the atmospheric turbulence into the boundary layer and to improve wind turbine noise emission models.