wind energy resource evaluation in a site of central italy ... - WindSim

the wind rose and the directions of the CFD results. To solve this problems, thesector interpolation function is helpful, in order to modify the CFD results.The wind directions found with the CFD must be referred at one direction of thewind rose and this is done by a linear interpolation procedure. For instance, thecorrect CFD velocity for the direction 30° is obtained weighting the two velocitiescalculated (2° and 35°) in which the 30° direction is comprised. The weight isproportional to the distance of the actual CFD velocity from the wind rose direction.Once this weighted average of sector 0 and 30 is done, the obtained dataset is usedto scale the experimental climatology data for sector 30, allowing the preparation ofthe wind resources map. This procedure is repeated for all the directional sectors atthe climatology.6.7.1 Mean wind velocityThe concept of the accuracy of the CFD calculation ha also been applied in the crosschecking procedure, and all the sector with a temporal frequency below 1,5 % havebeen excluded. Moreover, the conclusions valid for velocity vertical profiles havebeen also applied to the cross checking and the sectors in which the thermal effectsare strongly reduced have been highlighted with a red circle, i.e. the sectors forwhich U30 is included in or greater than the range 3 ÷ 4 m/s.In figures 6.8 the results of the cross-checking procedure by mean wind velocity arepresented. For instance in figure 6.8a, for each direction sector, the velocity on mast5424 in the period April-May, forecasted by data on mast 5428 at different height,are reported.109