Large-scale (that is over the kilometre scale of a whole wind farm) and small-scale (over the metre scale of an individual wind turbine) wind flow measurements are made with a mobile-based LIDAR system. The large-scale measurements detail the multiple wakes in the wind farm, including both single and double wakes, that result in up to 70% less power generation for a given wind direction, and 2.5% loss of the wind farm’s annual energy yield. The small-scale measurements show that there is a non-uniform work extraction of the turbine across the vertical extent of the wind turbine rotor. This non-uniform work extraction is accompanied by an upward pitching of the flow that is as much as 50° immediately downstream of the turbine and reduces to 10° two diameters downstream. Measurements with the mobile-based LIDAR system are made in both complex and flat terrains. A comparison of the wake profiles show that whereas in complex terrain the profiles are self-similar up to two-and-half rotor diameters downstream, this is not the case in flat terrain. It is shown that these measurements, which are made at the full-scale Reynolds number in the field, may be useful to support the development of wake flow prediction tools.

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