The calculation of the planform kinetic energy flux in this paper contains an error. The equation stated in the manuscript, P vert≈−ρA plan u<u′w′>, is correct. However, a typographical error in the data processing code had the effect of calculating the planform kinetic energy flux using u 2 instead of u. This error caused a quantitative change in the planform kinetic energy flux as can be seen in the revised version of .
Figure 1 Contours of the power transport due to the planform kinetic energy flux along the centre of the turbine array. The three turbine pairs are indicated as vertical bars.
Upon correction, the planform kinetic energy flux is lower than originally stated. In the region in front of the turbine array, it is 2.2 W/m2 instead of 17 W/m2. The average planform kinetic energy flux into the turbine array from 2 D downwind of the second turbine pair to 7.5 D downwind of the third sensor pair is 3.4 W/m2 for the highest sensor position and 0.03 W/m2 for the lowest sensor position; values of 22 W/m2 and 0.4 W/m2, respectively, were stated in the paper. The correction leads to a planform kinetic energy flux of 316 W per turbine pair which is approximately one-third of the power that is extracted by the turbine pair.
Furthermore, the corrected results lead to the conclusion that the Frandsen formula gives the better estimate of the planform kinetic energy flux. The Frandsen estimate is off by 76% while the Lettau is off by a factor of 8.5.
While the conclusions of the manuscript are largely unchanged, the corrected data indicate that the planform kinetic energy flux is not sufficient to account for the total power extraction by the wind turbines in the array. The frontal kinetic energy flux is also an important contributing factor, as is expected given that the experimental array does not operate in the limit of a steady-state wind turbine atmospheric boundary layer. The authors regret the error and any inconvenience caused by it.