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

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Table 6.1: Geometrical model characteristics.Geometrical modelTotal number of cells 3136000Extension Km 14,2 x 14,2x_resolutionmin 134 m – max 30 my_resolutionmin 134 m – max 30 mNumber of cells in x direction 280Number of cells in y direction 280Number of cells in z direction 40Height Distibution Factor 0,01Height of the model5000 mMinimum height of the first cell2,4 mMaximum height of the first cell3,2 mNumber of cells in first 100 m height 66.3 Numerical ModelThe 3D Wind Field of the site has been calculated through the WindSim software.This program is a powerful tool which solves the Reynolds Averaged Navier Stokes(RANS) equations for turbulent flows. The numerical model contains the continuityequation and the three momentum equations. The energy equation has not beensolved since thermal effects have not been considered in the simulations. Theclosure problem of turbulent flows has been solved by introducing the standard κ−εturbulence model. The boundary conditions and the settings for the solver are listedin table 6.291
Table 6.2: Boundary conditions and solver settingsBoundary conditionsTopwall with no frictionGeostrophic height500 mFree stream wind speed20 m/sWind directions12 sectorsTurbulence closureTurbulence modelstandard k-εYAP correctionenabledSolver settingsSolver typeSegregatedNumber of iteration 600Convergence Wizardenabled6.4 SimulationsThe total time needed to carry out the simulations was about 12 full days, one dayper sector. The computer used for the simulations was a Dell Precision T5400,equipped by a quad-core CPU Intel Xeon with frequency 2,33 GHz each and 8 GBytesof RAM.The residual values showing the obtained convergence level are shown in figure 6.1,for the simulations corresponding to the different directional sectors. A correctconvergence level has been obtained in each sector.Figure 6.1 a/b/c: Residual values for sectors 0, 30 and 60 degrees.92
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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
Page 49 and 50: H [m] hill heightν[m 2 /s] air cin
Page 51 and 52: Figure 3.18: Particular of the nume
Page 53 and 54: Finally, the horizontal x velocity
Page 55 and 56: Figure 3.25: Z velocity componentFi
Page 57 and 58: 3.6 RemarksA CFD study of a boundar
Page 59 and 60: Some experimental wind data of this
Page 61 and 62: Both the pictures 4.3 and 4.4 have
Page 63 and 64: 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: CHAPTER 6. Analysis of the wind fie
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 and 116: A general overview of the figure 6.
Page 117 and 118: 6.7 Cross Checking of wind dataIn t
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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