Suhas Pol
Texas Tech University
USA
Title: : Influence of atmospheric stability on model wind turbine wake interface
Biography
Biography: Suhas Pol
Abstract
Differences in wind turbine wake defect recovery for various atmospheric stabilities (stratification) has been attributed to turbulence intensity levels at different conditions. We show that buoyancy differences at the wind turbine wake interface should be considered in addition to varying turbulence intensity to describe the net momentum transport across the wake interface. These buoyancy differences are created due to the tip vortex, hub vortex or the swirl in the wake. The above hypothesis was tested using field measurements of the wake interface for a 1.25 m model turbine installed at 6.25m hub height., Atmospheric conditions were characterized using a 10 m tower upstream of the turbine, while a vertical rake of sonic anemometers clustered around the hub height on a downstream tower measured the wake. Data was collected over the course of seven months, during varying stability conditions, and with five different turbine configurations, including a single turbine at three different positions, two turbines in a column, and three turbines in a column. Presented are results showing the behavior of the wake (particularly the wake interface), for unstable, stable, and neutral conditions. It is observed that the swirl in the wake causes mixing of the inflow leading to a constant density profile in the wake leading to density jumps at the wake interfaces for stratified inflow. Contrasting spectral characteristics of the flow in the wake with respect to stability will be presented.