Wind speed reconstruction from three synchronized short-range WindScanner lidars in a large wind turbine inflow field campaign and the associated uncertainties

Abstract

Modern large wind turbines require high-resolution wind measurements as input to aerodynamic and aeroelastic simulations for modelling and validation purposes. Within the HighRe project, we aim at studying the aerodynamic effects at high Reynolds numbers by measuring four-dimensional wind fields (vx ,vy ,vz ,t) using three short-range WindScanners (SRWS). The systems were set up at the test site in Bremerhaven (Testfeld BHV) to perform an inflow wind field measurement campaign. In order to get a better understanding of the measurements, we describe the propagation of uncertainties in SRWS parameters to the measured wind field and propose an uncertainty model for a measurement setup with three SRWS lidars. In this study, we first evaluate the wind reconstruction and derive an uncertainty model for the wind components vx , vy , and vz , which are mainly dependent on the input parameters, e.g., focus range, elevation angle, and azimuth angle. The effective intersection diameter at the intersection of three beams was found to be in the order of 2-5m. As expected, a high uncertainty was observed at lower heights in the vz -component due to low elevation angles. This uncertainty evaluation forms the basis for comparing scanning patterns with regard to their accuracy in providing four-dimensional measurements.