A single pulsed Doppler wind lidar, deployed at the FINO1 platform in the North Sea, has been used to monitor the lateral and vertical coherence of the along-wind component. To maximize the sampling frequency of the monitoring system, a particular configuration based on small sweeping angles around the mean wind direction is used. The set-up provides wind velocity measurement with an increasing cross-flow separation with increasing distances from the lidar. We present hereby preliminary results from the analysis of the Plan Position Indicator scans carried out with a sampling frequency of 0.13 Hz, and the Range Height Indicator scans sampled at 0.19 Hz. The mean velocity and the turbulence intensity indicated a sufficiently uniform flow, which was verified by the calculation of the along and crosswind turbulence length scales. The lateral and vertical coherence was estimated based on multiple 10-minutes samples, for a mean wind velocity ranging from 10 to 14 m s-1. For the conditions examined, the measured coherence showed a good agreement with the IEC model for low and medium cross-flow separations, and a fairly good agreement with the Frøya model for large separations.
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机译:部署在北海FINO1平台上的单脉冲多普勒测风激光雷达已用于监测顺风分量的横向和垂直相干性。为了最大化监视系统的采样频率,使用了基于围绕平均风向的较小扫掠角的特定配置。该设置提供的风速测量具有随着与激光雷达的距离增加而增加的错流间隔。在此,我们提供对以0.13 Hz采样频率进行的“平面位置指示器”扫描和以0.19 Hz采样的“范围高度指示器”扫描进行分析的初步结果。平均速度和湍流强度表明流量足够均匀,这已通过沿顺风和逆风湍流长度尺度的计算得到了验证。横向和垂直连贯性是基于多个10分钟的样本估算的,平均风速范围为10到14 m s-1。在所检查的条件下,测量的相干性对于低和中等错流分离显示出与IEC模型的良好一致性,对于大分离分离,与Frøya模型的一致性很好。
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