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

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Figure 6.7: Relation between RMS errors and U30.107
6.7 Cross Checking of wind dataIn the following paragraphs the cross checking of the experimental data, asexplained in chapter 1, is presented. The WindSim feature, called transferredclimatology object, was used. As previously described when multiple measurementmasts are available in one site, it is possible to predict by CFD calculation the windresources in one measurement station using data available in the othermeasurement station. In other words, it’s possible to transfer wind data from theoriginal position to the other taking into account the different orographic androughness effectsThe cross checking has been studied using two different procedures, using as scalingvariable the mean wind velocity per sector and the speed-up values, respectively.In the first case the experimental mean velocity values have been extracted by thetime history, while all the CFD values have been calculated using the sectorinterpolation function [4] of WindSim.In the second case, relative to the speed-up calculation, two methods have beenused, one considering the sector interpolation and the other one without thisoption. Concerning the experimental speed-up, this value was calculated directlyfrom experimental dataset, by a ratio between the mean velocity in the referencemast and the mean velocity in the new position.Sector interpolationThe sector interpolation function is a correction function of WindSim, needed whenthe CFD results must be weighted against one experimental data-set, in order todetermine the horizontal wind speed map.When the wind direction boundary condition is given, it is applied at the boundariesof the model, by describing a geostrophic wind. Nevertheless the wind evaluated inthe internal zone can be deviated by orographic effects, especially close to theground. For instance, if two simulations are run for sectors 0° and 30° as boundaryconditions, in the center of the domain the wind direction could be, for instance, 2°and 35° respectively. In this case there will be a mismatch between the directions of108
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UNIVERSITÀ DEGLI STUDI DI CAGLIARI
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IndexIndex page IAcknowledgmentsVII
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CHAPTER 4: Characteristics of the s
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6.7.1 Mean wind velocity page 1096.
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This thesis is the result of a prac
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WindSim is a software developed by
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CHAPTER 1. Atmospheric Boundary Lay
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Figure 1.1: Example of an atmospher
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1.5 The WindSim numerical codeWindS
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(κ−ε RNG or the Low Reynolds),
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1.5.4 RESULTSThe Results module all
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Figure 1.2: Example of TKE vertical
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CHAPTER 2. Simulations over flat te
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inlet position (0 meters), station
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2.4 Height distribution factor sens
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e decreased, to avoid to build thin
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Figure 2.10: Vertical profiles for
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CHAPTER 3. Simulations over 2D hill
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Table 3.1: Measurement coordinatesS
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The results shown above demonstrate
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Figure 3.6: Sketch of the 15 km lon
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Figure 3.9: Influence of the height
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Figure 3.13: Zoom of the hill top r
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3.5.2) = ∙.The two models for att
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H [m] hill heightν[m 2 /s] air cin
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Figure 3.18: Particular of the nume
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Finally, the horizontal x velocity
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Figure 3.25: Z velocity componentFi
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3.6 RemarksA CFD study of a boundar
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Some experimental wind data of this
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Both the pictures 4.3 and 4.4 have
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Table 4.2: Description of the color
Page 65 and 66: In this periods, data are recorded
Page 67 and 68: In the following pages, a short des
Page 69 and 70: 4.3.2 Mast 5424-15 m Period April-M
Page 71 and 72: 4.3.4 Mast 5424-15 m Period Novembe
Page 73 and 74: 4.3.6 Mast 5428-40 m Period April-M
Page 75 and 76: 4.3.8 Mast 5428-50 m Period Novembe
Page 77 and 78: 4.3.10 Mast 5428-30 m Period Novemb
Page 79 and 80: 4.4.2 Mast 542870
Page 81 and 82: 4.5.2 Mast 542872
Page 83 and 84: CHAPTER 5. Test of the Free Stream
Page 85 and 86: case the wind is blowing from the e
Page 87 and 88: Geometrical modelTable 5.3: Input p
Page 89 and 90: Figure 5.6: Vertical profiles in po
Page 91 and 92: The orthogonalization of the grid h
Page 93 and 94: Figure 5.9: Map of speed-ups for di
Page 95 and 96: Figure 5.30: Speed-2D at 30 m heigh
Page 97 and 98: Figure 5.12: Speed-2D at 30 m heigh
Page 99 and 100: CHAPTER 6. Analysis of the wind fie
Page 101 and 102: Table 6.2: Boundary conditions and
Page 103 and 104: 6.5 Vertical profiles of VelocityTo
Page 105 and 106: characterized by high wind speed (5
Page 107 and 108: From the error analysis, it is foun
Page 109 and 110: Anyhow, the trend of the linear int
Page 111 and 112: Concerning the CFD simulations, val
Page 113 and 114: Analyzing RMS error table for tower
Page 115: A general overview of the figure 6.
Page 119 and 120: Figure 6.8 a/bFigure 6.8 c/dFigure
Page 121 and 122: Table 6.11: RMS error for cross che
Page 123 and 124: Figure 6.9 e/fFigure 6.9 g/hFigure
Page 125 and 126: Figure 6.10 g/hFigure 6.10 i/lFigur
Page 127 and 128: to have a better agreement during t
Page 129 and 130: Figure 7.2: Weibull fitting of the
Page 131 and 132: Figure 7.5: Perspective view of the
Page 133 and 134: The calculated AEP has been reporte
Page 135 and 136: ConclusionsIn this thesis the evalu
Page 137 and 138: Bibliography[1] CRASTO G. - Numeric
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