Wake measurements of a multi-MW wind turbine with long range lidar

The 2-µm pulsed Doppler lidar of the DLR (Deutsches Zentrum für Luft- und Raumfahrt) was used to carry out wake measurements of a 5 MW wind turbine of the type Multibrid M5000. This prototype offhsore wind turbine is operating in Bremerhaven at a site near the coast line. The maximum range of the lidar is more than ten kilometres and thus we were able to cover the wind field area of inflow, near-wake and far-wake. For data acquisition a range of 2.5 kilometers, which includes more than ten diameters downstream, was used. First results of different scanning techniques, which demonstrate the potential of this type of measurements, will be presented

Theoretical and methodological considerations for the study of banal and everyday nationalism

Theoretical and methodological considerations for the study of banal and everyday nationalis

The wake of a wind turbine and its influence on sound propagation

The wake of a single wind turbine was measured with a Doppler wind lidar system during a night with a well developed low-level jet. Two meteorological microscale models with different model assumptions were applied to the same situation to generate consistent three-dimensional fields of wind components, turbulent kinetic energy and temperature. A three-dimensional ray-based sound particle model was used to simulate the propagation of the wind turbine noise into the downwind area. Two-dimensional sound propagation simulations were performed on the basis of the lidar measurements and three-dimensional simulations were based on the results of the meteorological models. Both meteorological models are capable of reproducing the main features of the measured wake flow. However, the results differ in many details from each other as well as from the lidar measurements. The acoustical model results show that the wake flow favours the sound propagation from the upper sources (aerodynamic noise at the wing tips near the crest of the rotor plane) towards the ground. The acoustical simulations also suggest a high sensitivity of the noise impact near the ground to differences between the simulated meteorological fields

Wake measurements of a multi-MW wind turbine with coherent long-range pulsed doppler wind lidar

Long-range Doppler wind light detection and ranging (lidar) measurements at a wind turbine were carried out for the first time. The turbine was of the type Areva M5000 and is located at a site near the coastline in Bremerhaven, in the northern part of Germany. This wind turbine is the prototype for the German offshore test site ‘‘alpha ventus’’ and has a rated power of 5 MW. Information about the ambient wind field before and after this multimegawatt wind turbine was obtained. In this paper the measurement technique is discussed and the results of measurements in the diurnal layer and in the stable nocturnal boundary layer are shown. The main focus of this work is to determine the reduction of the wind speed at certain distances downstream from the rotor