Page 101 - Fluid Power Engineering
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W i nd Measurement    79



























              FIGURE 6-3 Sonic anemometer to measure all three components of wind
              velocity. (With permission of Campbell Scientific, CSAT3 3-D sonic
              anemometer.)

              where k is the class index, ε i is the maximum systematic deviation, and
             U i is the wind speed in bin i. Figure 6-4 is a plot of the accuracy curves
              for different classes. For convenience, instead of curves describing
              classes, often a single point is used, U i = 10 m/s, and accuracy is
              then defined as percentage deviation in anemometer measurement in
























              FIGURE 6-4 Deviations chart used to classify anemometers per IEC
                                                          .
              61400-12-1. [From Dahlberg, J. A., Pedersen, T. F., Busche, P ACCUWIND-
              Methods for Classification of Cup Anemometers, Riso National Laboratory,
              Roskilde, 2006. Riso-R-1555(EN).]
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