Posters

Abstract

By focusing all the laser power at each specific measurement distance in sequence, continuous wave (CW) lidar achieves very high sensitivity, and this in turn allows measurements to be performed over a short integration time. Here, we demonstrate the benefits of this rapid data rate to the wind industry in several important applications, using example measurements with systems from ZX Lidars, which run with a default integration time of 20.48 milliseconds, giving a 48.8 Hz data rate. The advantages conferred by such rapid measurements fall into three main areas. Firstly, where the lidar is mounted on a moving platform such as a floating buoy, a turbine nacelle or a rotating turbine blade, any motion is effectively frozen over the short integration time, whereas significant smearing can occur in systems that must measure over a longer period, with a resulting loss in precision. Secondly, the method allows rapid interrogation of the wind field over a wide area, and this is important in applications such as turbine control (where the value of the data is very short-lived, and must be acted upon within seconds), and in complex flows (measured either from the ground or from a turbine nacelle) where otherwise only a small number of sample measurements can provide a very incomplete wind field characterisation. Thirdly, with the appropriate measurement geometry, the rapid data rate permits investigation of turbulence in fluctuating flows at a sample rate approaching that of a sonic anemometer.