Influence of complex terrain on a flow above a forest with clearing

Paper i proceeding, 2020

Large Eddy simulations is compared to LiDAR measurements for the Lemnhult wind farm in Sweden. Two scans are performed, the south to represent a forest flow and the west to represent a flow over a clearing. A forest model is implemented in STAR-CCM+ and the local forest height at the site is used. The terrain height is included in the simulations to investigate its effect. The complex terrain simulations show the best agreement with the measurement. The uncertainty of the stratification of the measurements can be the reason for some of the difference. The vertical wind speed for the clearing scan changes a lot when the complex terrain is included, but its magnitudes are however still low compared to the horizontal velocity. This shows the importance of including complex terrain for simulations with large change in terrain height. The normalized turbulent kinetic energy for the vertical profiles is showing a decrease in the clearing scan compared to the forest scan which should be beneficial for wind turbines.