Laser scanning of a recirculation zone on the Bolund escarpment

The Science of Making Torque from Wind 2012

Mann, J.^1 ; Angelou, N.^1 ; Sjöholm, M.^1 ; Mikkelsen, T.^1 ; Hansen, K.H.^1 ; Cavar, D.^1 ; Berg, J.^1

Technical University of Denmark, Department of Wind Energy, Risø Campus, Frederiksborgvej 399, Roskilde

4000, Denmark^1

关键词: Beam direction;    Computational fluid dynamics models;    Laser scanning;    Maximum velocity;    Rapid variation;    Recirculation zones;    Sharp interface;    Standard deviation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/555/1/012066/pdf
DOI  :  10.1088/1742-6596/555/1/012066

来源: IOP

【 摘 要 】

Rapid variations in the height of the recirculation zone are measured with a scanning wind lidar over a small escarpment on the Bolund Peninsula. The lidar is essentially a continuous-wave laser Doppler anemometer with the capability of rapidly changing the focus distance and the beam direction. The instrument measures the line-of-sight velocity 390 times per second and scans ten wind profiles from the ground up to seven meters per second. We observe a sharp interface between slow and fast moving fluid after the escarpment, and the interface is moving rapidly up and down. This implies that the position of the maximum velocity standard deviation is elevated a few meters above the surface. Close to the ground the mean wind is reversed relative to the general flow. The results are used to test computational fluid dynamics models for flow over terrain, and has relevance for wind energy. The preliminary comparison shows that the models are incapable of reproducing the reversed flow close to the surface, but more works needs to be done.