PNNL

Abstract

The interplay of momentum within wind farms significantly influences wake recovery, affecting the speed at which wakes return to their free-stream velocities. Under stable atmospheric conditions, wind farm wakes can extend over considerable distances, leading to sustained vertical momentum flux downstream, with variations observed throughout the diurnal cycle. Particularly in regions such as the US Great Plains, stable conditions can induce low-level jets, impacting wind farm performance and power output. This study examines the implications of wake recovery using extensive observations of vertical momentum flux across diverse atmospheric conditions. Key findings include: prolonged wake propagation during stability, alterations to low-level jet characteristics downstream of wind farms, the notable impact of low-level jet height on wake recovery, wake propagation even under negative wind shear in non-low-level jet scenarios, detection of wake effects via d, enhancement of wake recovery by gravity waves, and the effective performance of large-eddy simulation-based models incorporating real-world atmospheric and turbine inputs. These insights deepen our understanding of the intricate dynamics governing wake recovery in wind farms, advancing efforts to model and predict their behavior across varying atmospheric contexts.