Hi @Jason.Jonkman:
Also in InflowWind when you output wind velocity where is it saved and how could I plot it.
Regards,
AOAW
Dear @Andre.White,
The FFwind_figure.m script will plot the TurbSim wind data including shear + turbulence.
The wind data outputs identified in the OutList of InflowWind will be included along with the rest of the module outputs in the OpenFAST time series output file.
Best regards,
Thank you @Jason.Jonkman. The plots for u,w and v are shown separately, but there are 3 -axes each, how do i know which face of the cube i should read from to get shear and turbulence for example. Don’t understand.
Regards,
AOAW
Dear @Andre.White,
I have not actually used this script myself. But each figure shows the U, V, or W data in a 3D graph as a function of two spatial dimensions (Y,Z) and one time dimension.
Best regards,
1 Like
Hi @Jason.Jonkman I have done the plots of the wind field with FFwind.
I have attached 3 plots of the u-component of the wind field. The component that constitutes the turbulent wind. 1) u-wind is for 65.8 m/s wind and TI of 8.25%, 2) u-wind-shear uses a particular wind shear profile, where the wind speed at hub height is 65.8 m/s, a coherence exponent of 0.85 and 3) u-wind-shear-veer is similar to 2) but utilizes the veer profile.
I realize that the u-component of the wind when veer is considered, show negative values. In addition, I see that the maximum wind speed for option 2 when wind shear profile is used is less than the wind speed for option 1.
I would like to know if you have any thoughts on this as I thought the cases that considered the coherence exponent, the shear and veer profile would have offered more onerous wind speeds than option 1. Also, the negative wind speeds when veer is considered does not seem correct.
Hope I am clear but hope you can assist.
Regards,
AOAW
Hi @Jason.Jonkman one of the things I would like to ascertain is why the wind speed for the veer in the u-direction is negative. Would be grateful for your assistance.
Regards,
AOAW
Dear @Andre.White,
You haven’t explained how you set up your TurbSim file, so, I’m not sure I fully understand what is different between cases (1), 2), and (3).
Regardless, I would suggest building up complexity in steps, e.g., first simulate without turbulence (IECturbc = 0) with your shear and veer to verify it is what you expect, then add turbulence.
Best regards,
Ok @Jason.Jonkman thank you.
Regards,
AOAW
Hi @Jason.Jonkman I simulated using the veer profile without considering turbulence. The u-component wind speeds are still negative. I am not certain why that is the case. Based on the TurbSim manual, I thought the u-component wind speeds would have been positive values. So these are the conditions that I modelled:
- 65.8 m/s URef and 8.25% TI, PL profile
- 65.8 m/s 8.25% TI and user-defined wind shear profile (during hurricane), coherence exponent = 0.85
- 65.8 ms 8.25% TI; user defined wind shear/veer profile (during hurricane), coherence exponent =0.85
I was expecting 2 and 3 to be more onerous than 1, given use of coherence exponent and the user-defined profiles (during hurricane) but that is not the case. In fact some of the responses on the turbine are more onerous than 1. What I wanted to show was that if use of the user-defined profile in addition to the coherence exponent would give more onerous conditions than just using URef, TI and PL profile. That is why I wanted to view the u-component of wind speed to see if I could spot any differences but I could not see distinct difference from the 3D plots. Just checking to see if you have any further thoughts on this, as I am now bemused.
Regards,
AOAW
Dear @Andre.White,
I’m sorry, but I’m not understanding. You mentioned simulating without turbulence, but all three of your conditions list a TI. I’m also not sure what is different between condition 2 and 3.
Best regards,
Hi @Jason.Jonkman sorry about that.
Condition 1a, say, I mentioned in the first line that has no TI
Then condition 1
The difference between 2 and 3 is that 2 has shear profile; and 3 has shear and veer profile.
Hope that is clear.
Regards,
AOAW
Hi @Jason.Jonkman to make it even more clear, I am including the relevant sections from TurbSim (options revised):
- 65.8 m/s, TI=0, user-defined wind shear_veer profile;
--------Meteorological Boundary Conditions-------------------(“IECKAI”,“IECVKM”,“GP_LLJ”,“NWTCUP”,“SMOOTH”,“WF_UPW”,“WF_07D”,“WF_14D”,“TIDAL”,“API”,“USRINP”,“TIMESR”, or “NONE”)
“unused” UserFile - Name of the file that contains inputs for user-defined spectra or time series inputs (used only for “USRINP” and “TIMESR” models)
“1-ED2” IECstandard - Number of IEC 61400-x standard (x=1,2, or 3 with optional 61400-1 edition number (i.e. “1-Ed2”) )
0.0 IECturbc - IEC turbulence characteristic (“A”, “B”, “C” or the turbulence intensity in percent) (“KHTEST” option with NWTCUP model, not used for other models)
“NTM” IEC_WindType - IEC turbulence type (“NTM”=normal, “xETM”=extreme turbulence, “xEWM1”=extreme 1-year wind, “xEWM50”=extreme 50-year wind, where x=wind turbine class 1, 2, or 3)
“default” ETMc - IEC Extreme Turbulence Model “c” parameter [m/s]
“USR” WindProfileType - Velocity profile type (“LOG”;“PL”=power law;“JET”;“H2L”=Log law for TIDAL model;“API”;“USR”;“TS”;“IEC”=PL on rotor disk, LOG elsewhere; or “default”)
“windshear_veer5.dat” ProfileFile - Name of the file that contains input profiles for WindProfileType=“USR” and/or TurbModel=“USRVKM” [-]
119.0 RefHt - Height of the reference velocity (URef) [m]
“default” URef - Mean (total) velocity at the reference height [m/s] (or “default” for JET velocity profile) [must be 1-hr mean for API model; otherwise is the mean over AnalysisTime seconds]
“default” ZJetMax - Jet height [m] (used only for JET velocity profile, valid 70-490 m)
“default” PLExp - Power law exponent [-] (or “default”)
“default” Z0 - Surface roughness length [m] (or “default”)
- 65.8 m/s, TI=8.25%, user-defined wind shear profile, coherence exponent =0.85
--------Meteorological Boundary Conditions-------------------
“IECKAI” TurbModel - Turbulence model (“IECKAI”,“IECVKM”,“GP_LLJ”,“NWTCUP”,“SMOOTH”,“WF_UPW”,“WF_07D”,“WF_14D”,“TIDAL”,“API”,“USRINP”,“TIMESR”, or “NONE”)
“unused” UserFile - Name of the file that contains inputs for user-defined spectra or time series inputs (used only for “USRINP” and “TIMESR” models)
“1-ED2” IECstandard - Number of IEC 61400-x standard (x=1,2, or 3 with optional 61400-1 edition number (i.e. “1-Ed2”) )
8.25 IECturbc - IEC turbulence characteristic (“A”, “B”, “C” or the turbulence intensity in percent) (“KHTEST” option with NWTCUP model, not used for other models)
“NTM” IEC_WindType - IEC turbulence type (“NTM”=normal, “xETM”=extreme turbulence, “xEWM1”=extreme 1-year wind, “xEWM50”=extreme 50-year wind, where x=wind turbine class 1, 2, or 3)
“default” ETMc - IEC Extreme Turbulence Model “c” parameter [m/s]
“USR” WindProfileType - Velocity profile type (“LOG”;“PL”=power law;“JET”;“H2L”=Log law for TIDAL model;“API”;“USR”;“TS”;“IEC”=PL on rotor disk, LOG elsewhere; or “default”)
“windshear5.dat” ProfileFile - Name of the file that contains input profiles for WindProfileType=“USR” and/or TurbModel=“USRVKM” [-]
119 RefHt - Height of the reference velocity (URef) [m]
65.8 URef - Mean (total) velocity at the reference height [m/s] (or “default” for JET velocity profile) [must be 1-hr mean for API model; otherwise is the mean over AnalysisTime seconds]
“default” ZJetMax - Jet height [m] (used only for JET velocity profile, valid 70-490 m)
“default” PLExp - Power law exponent [-] (or “default”)
“default” Z0 - Surface roughness length [m] (or “default”)
--------Spatial Coherence Parameters----------------------------
“General” SCMod1 - u-component coherence model (“GENERAL”, “IEC”, “API”, “NONE”, or “default”)
“General” SCMod2 - v-component coherence model (“GENERAL”, “IEC”, “NONE”, or “default”)
“General” SCMod3 - w-component coherence model (“GENERAL”, “IEC”, “NONE”, or “default”)
“default” InCDec1 - u-component coherence parameters for general or IEC models [-, m^-1] (e.g. “10.0 0.3e-3” in quotes) (or “default”)
“default” InCDec2 - v-component coherence parameters for general or IEC models [-, m^-1] (e.g. “10.0 0.3e-3” in quotes) (or “default”)
“default” InCDec3 - w-component coherence parameters for general or IEC models [-, m^-1] (e.g. “10.0 0.3e-3” in quotes) (or “default”)
0.85 CohExp - Coherence exponent for general model [-] (or “default”)
- 65.8 m/s, TI=8.25%, user-defined wind shear profile and user-defined wind veer profile, coherence exponent = 0.85
-Meteorological Boundary Conditions-------------------
“IECKAI” TurbModel - Turbulence model (“IECKAI”,“IECVKM”,“GP_LLJ”,“NWTCUP”,“SMOOTH”,“WF_UPW”,“WF_07D”,“WF_14D”,“TIDAL”,“API”,“USRINP”,“TIMESR”, or “NONE”)
“unused” UserFile - Name of the file that contains inputs for user-defined spectra or time series inputs (used only for “USRINP” and “TIMESR” models)
“1-ED2” IECstandard - Number of IEC 61400-x standard (x=1,2, or 3 with optional 61400-1 edition number (i.e. “1-Ed2”) )
8.25 IECturbc - IEC turbulence characteristic (“A”, “B”, “C” or the turbulence intensity in percent) (“KHTEST” option with NWTCUP model, not used for other models)
“NTM” IEC_WindType - IEC turbulence type (“NTM”=normal, “xETM”=extreme turbulence, “xEWM1”=extreme 1-year wind, “xEWM50”=extreme 50-year wind, where x=wind turbine class 1, 2, or 3)
“default” ETMc - IEC Extreme Turbulence Model “c” parameter [m/s]
“USR” WindProfileType - Velocity profile type (“LOG”;“PL”=power law;“JET”;“H2L”=Log law for TIDAL model;“API”;“USR”;“TS”;“IEC”=PL on rotor disk, LOG elsewhere; or “default”)
“windshear_veer5_rev1.dat” ProfileFile - Name of the file that contains input profiles for WindProfileType=“USR” and/or TurbModel=“USRVKM” [-]
119 RefHt - Height of the reference velocity (URef) [m]
65.8 URef - Mean (total) velocity at the reference height [m/s] (or “default” for JET velocity profile) [must be 1-hr mean for API model; otherwise is the mean over AnalysisTime seconds]
“default” ZJetMax - Jet height [m] (used only for JET velocity profile, valid 70-490 m)
“default” PLExp - Power law exponent [-] (or “default”)
“default” Z0 - Surface roughness length [m] (or “default”)
Spatial Coherence Parameters----------------------------
“general” SCMod1 - u-component coherence model (“GENERAL”, “IEC”, “API”, “NONE”, or “default”)
“general” SCMod2 - v-component coherence model (“GENERAL”, “IEC”, “NONE”, or “default”)
“general” SCMod3 - w-component coherence model (“GENERAL”, “IEC”, “NONE”, or “default”)
“default” InCDec1 - u-component coherence parameters for general or IEC models [-, m^-1] (e.g. “10.0 0.3e-3” in quotes) (or “default”)
“default” InCDec2 - v-component coherence parameters for general or IEC models [-, m^-1] (e.g. “10.0 0.3e-3” in quotes) (or “default”)
“default” InCDec3 - w-component coherence parameters for general or IEC models [-, m^-1] (e.g. “10.0 0.3e-3” in quotes) (or “default”)
0.85 CohExp - Coherence exponent for general model [-] (or “default”)
Wind shear profile
| ---------TurbSim v2.00.* Profile Input File------------------------ | |||
|---|---|---|---|
| Example file using completely made up profiles | |||
| -------- User-Defined Profiles (Used only with USR wind profile or USRVKM | spectral | model) | ------------- |
| 239 NumUSRz - Number of Heights | |||
| 1.092 StdScale1 - u-component scaling factor for the input | standard | deviat | ion |
| 1.0 StdScale2 - v-component scaling factor for the input | standard | deviat | ion |
| 0.534 StdScale3 - w-component scaling factor for the input | standard | deviat | ion |
| ------------------------------------------------------------------------- | --------- | - | |
| Height Wind Speed Wind Direction Standard Deviation | Length Sc | ale | |
| (m) (m/s) (deg, cntr-clockwise ) (m/s) | (m) | ||
| ------------------------------------------------------------------------- | --------- | - | |
| 8.94 | 51.96 | 0 | |
| 9 | 51.99 | 0 | |
| 10 | 52.44 | 0 | |
| 11 | 52.89 | 0 | |
| 12 | 53.34 | 0 | |
| 12.5 | 53.56 | 0 | |
| 13 | 53.8 | 0 | |
| 14 | 54.27 | 0 | |
| 15 | 54.74 | 0 | |
| 15.73 | 55.08 | 0 | |
| 16 | 55.21 | 0 | |
| 17 | 55.68 | 0 | |
| 18 | 56.15 | 0 | |
| 19 | 56.62 | 0 | |
| 19.25 | 56.74 | 0 | |
| 20 | 57.08 | 0 | |
| 21 | 57.55 | 0 | |
| 22 | 58.01 | 0 | |
| 22.63 | 58.3 | 0 | |
| 23 | 58.4 | 0 | |
| 24 | 58.66 | 0 | |
| 25 | 58.92 | 0 | |
| 26 | 59.19 | 0 | |
| 27 | 59.45 | 0 | |
| 28 | 59.72 | 0 | |
| 28.74 | 59.91 | 0 | |
| 29 | 59.96 | 0 | |
| 30 | 60.18 | 0 | |
| 31 | 60.39 | 0 | |
| 32 | 60.6 | 0 | |
| 33 | 60.81 | 0 | |
| 34 | 61.02 | 0 | |
| 34.64 | 61.16 | 0 | |
| 35 | 61.22 | 0 | |
| 36 | 61.4 | 0 | |
| 37 | 61.57 | 0 | |
| 38 | 61.75 | 0 | |
| 39 | 61.93 | 0 | |
| 40 | 62.11 | 0 | |
| 41 | 62.29 | 0 | |
| 41.95 | 62.45 | 0 | |
| 42 | 62.46 | 0 | |
| 43 | 62.64 | 0 | |
| 44 | 62.82 | 0 | |
| 45 | 63 | 0 | |
| 46 | 63.17 | 0 | |
| 47 | 63.35 | 0 | |
| 48 | 63.53 | 0 | |
| 49 | 63.71 | 0 | |
| 50 | 63.88 | 0 | |
| 50.84 | 63.49 | 0 | |
| 51 | 63.51 | 0 | |
| 52 | 63.63 | 0 | |
| 53 | 63.75 | 0 | |
| 54 | 63.86 | 0 | |
| 55 | 63.98 | 0 | |
| 56 | 64.1 | 0 | |
| 57 | 64.21 | 0 | |
| 58 | 64.33 | 0 | |
| 59 | 64.45 | 0 | |
| 60 | 64.56 | 0 | |
| 60.82 | 64.27 | 0 | |
| 61 | 64.28 | 0 | |
| 62 | 64.34 | 0 | |
| 63 | 64.39 | 0 | |
| 64 | 64.44 | 0 | |
| 65 | 64.5 | 0 | |
| 66 | 64.55 | 0 | |
| 67 | 64.6 | 0 | |
| 68 | 64.66 | 0 | |
| 69 | 64.71 | 0 | |
| 70 | 64.76 | 0 | |
| 71 | 64.82 | 0 | |
| 71.49 | 64.84 | 0 | |
| 72 | 64.86 | 0 | |
| 73 | 64.89 | 0 | |
| 74 | 64.91 | 0 | |
| 75 | 64.94 | 0 | |
| 76 | 64.97 | 0 | |
| 77 | 65 | 0 | |
| 78 | 65.03 | 0 | |
| 79 | 65.05 | 0 | |
| 80 | 65.08 | 0 | |
| 81 | 65.11 | 0 | |
| 82 | 65.14 | 0 | |
| 83 | 65.17 | 0 | |
| 84 | 65.19 | 0 | |
| 84.45 | 65.21 | 0 | |
| 85 | 65.22 | 0 | |
| 86 | 65.24 | 0 | |
| 87 | 65.26 | 0 | |
| 88 | 65.29 | 0 | |
| 89 | 65.31 | 0 | |
| 90 | 65.33 | 0 | |
| 91 | 65.35 | 0 | |
| 92 | 65.37 | 0 | |
| 93 | 65.4 | 0 | |
| 94 | 65.42 | 0 | |
| 95 | 65.44 | 0 | |
| 96 | 65.46 | 0 | |
| 96.2 | 65.47 | 0 | |
| 97 | 65.48 | 0 | |
| 98 | 65.49 | 0 | |
| 99 | 65.5 | 0 | |
| 100 | 65.51 | 0 | |
| 101 | 65.52 | 0 | |
| 102 | 65.53 | 0 | |
| 103 | 65.54 | 0 | |
| 104 | 65.55 | 0 | |
| 105 | 65.56 | 0 | |
| 105.87 | 65.57 | 0 | |
| 106 | 65.57 | 0 | |
| 107 | 65.59 | 0 | |
| 108 | 65.61 | 0 | |
| 109 | 65.63 | 0 | |
| 110 | 65.64 | 0 | |
| 111 | 65.66 | 0 | |
| 112 | 65.68 | 0 | |
| 113 | 65.69 | 0 | |
| 114 | 65.71 | 0 | |
| 115 | 65.73 | 0 | |
| 116 | 65.75 | 0 | |
| 117 | 65.76 | 0 | |
| 117.9 | 65.78 | 0 | |
| 118 | 65.78 | 0 | |
| 119 | 65.8 | 0 | |
| 120 | 65.82 | 0 | |
| 121 | 65.84 | 0 | |
| 122 | 65.86 | 0 | |
| 123 | 65.87 | 0 | |
| 124 | 65.89 | 0 | |
| 125 | 65.91 | 0 | |
| 126 | 65.93 | 0 | |
| 127 | 65.95 | 0 | |
| 128 | 65.97 | 0 | |
| 129 | 65.99 | 0 | |
| 129.02 | 65.99 | 0 | |
| 130 | 66 | 0 | |
| 131 | 66.02 | 0 | |
| 132 | 66.04 | 0 | |
| 133 | 66.06 | 0 | |
| 134 | 66.07 | 0 | |
| 135 | 66.09 | 0 | |
| 136 | 66.11 | 0 | |
| 137 | 66.12 | 0 | |
| 138 | 66.14 | 0 | |
| 139 | 66.16 | 0 | |
| 140 | 66.18 | 0 | |
| 141 | 66.19 | 0 | |
| 141.06 | 66.19 | 0 | |
| 142 | 66.21 | 0 | |
| 143 | 66.24 | 0 | |
| 144 | 66.26 | 0 | |
| 145 | 66.28 | 0 | |
| 146 | 66.3 | 0 | |
| 147 | 66.32 | 0 | |
| 148 | 66.34 | 0 | |
| 149 | 66.36 | 0 | |
| 150 | 66.38 | 0 | |
| 151 | 66.4 | 0 | |
| 152 | 66.43 | 0 | |
| 153 | 66.45 | 0 | |
| 153.34 | 66.45 | 0 | |
| 154 | 66.47 | 0 | |
| 155 | 66.5 | 0 | |
| 156 | 66.52 | 0 | |
| 157 | 66.55 | 0 | |
| 158 | 66.57 | 0 | |
| 159 | 66.6 | 0 | |
| 160 | 66.62 | 0 | |
| 161 | 66.65 | 0 | |
| 162 | 66.68 | 0 | |
| 163 | 66.7 | 0 | |
| 164 | 66.73 | 0 | |
| 165 | 66.75 | 0 | |
| 165.5 | 66.77 | 0 | |
| 166 | 66.78 | 0 | |
| 167 | 66.8 | 0 | |
| 168 | 66.83 | 0 | |
| 169 | 66.85 | 0 | |
| 170 | 66.88 | 0 | |
| 171 | 66.91 | 0 | |
| 172 | 66.93 | 0 | |
| 173 | 66.96 | 0 | |
| 174 | 66.98 | 0 | |
| 175 | 67.01 | 0 | |
| 175.71 | 67.03 | 0 | |
| 176 | 67.03 | 0 | |
| 177 | 67.06 | 0 | |
| 178 | 67.09 | 0 | |
| 179 | 67.12 | 0 | |
| 180 | 67.15 | 0 | |
| 181 | 67.18 | 0 | |
| 182 | 67.21 | 0 | |
| 183 | 67.24 | 0 | |
| 184 | 67.27 | 0 | |
| 185 | 67.3 | 0 | |
| 186 | 67.33 | 0 | |
| 187 | 67.36 | 0 | |
| 188 | 67.38 | 0 | |
| 188.17 | 67.39 | 0 | |
| 189 | 67.41 | 0 | |
| 190 | 67.43 | 0 | |
| 191 | 67.45 | 0 | |
| 192 | 67.48 | 0 | |
| 193 | 67.5 | 0 | |
| 194 | 67.52 | 0 | |
| 195 | 67.54 | 0 | |
| 196 | 67.57 | 0 | |
| 197 | 67.59 | 0 | |
| 198 | 67.61 | 0 | |
| 199 | 67.63 | 0 | |
| 200 | 67.66 | 0 | |
| 200.42 | 67.67 | 0 | |
| 201 | 67.68 | 0 | |
| 202 | 67.7 | 0 | |
| 203 | 67.72 | 0 | |
| 204 | 67.73 | 0 | |
| 205 | 67.75 | 0 | |
| 206 | 67.77 | 0 | |
| 207 | 67.79 | 0 | |
| 208 | 67.81 | 0 | |
| 209 | 67.83 | 0 | |
| 210 | 67.85 | 0 | |
| 210.45 | 67.86 | 0 | |
| 211 | 67.87 | 0 | |
| 212 | 67.88 | 0 | |
| 213 | 67.9 | 0 | |
| 214 | 67.91 | 0 | |
| 215 | 67.93 | 0 | |
| 216 | 67.95 | 0 | |
| 217 | 67.96 | 0 | |
| 218 | 67.98 | 0 | |
| 219 | 68 | 0 | |
| 220 | 68.01 | 0 | |
| 221 | 68.03 | 0 | |
| 222 | 68.04 | 0 | |
| 223 | 68.06 | 0 | |
| 223.27 | 68.06 | 0 |
Wind shear and wind veer profile
---------TurbSim v2.00.* Profile Input File------------------------
Example file using completely made up profiles
-------- User-Defined Profiles (Used only with USR wind profile or USRVKM spectral model)
24 NumUSRz - Number of Heights
1.092 StdScale1 - u-component scaling factor for the input standard deviat
1.0 StdScale2 - v-component scaling factor for the input standard deviat
0.534 StdScale3 - w-component scaling factor for the input standard deviat
Height Wind Speed Wind Direction Standard Deviation Length Sc ale
“”“(m) (m/s) (deg, cntr-clockwise ) (m/s)” “(m)”“”
8.94 51.96 136.69
12.5 53.56 136.01
15.73 55.08 136.87
19.25 56.74 132.76
22.63 58.3 137.14
28.74 59.91 137.56
34.64 61.16 136.85
41.95 62.45 136.97
50.84 63.49 136.29
60.82 64.27 135.38
71.49 64.84 134.33
84.45 65.21 132.74
96.2 65.47 131.2
105.87 65.57 130.18
117.9 65.78 129.36
129.02 65.99 128.57
141.06 66.19 125.92
153.34 66.45 117.2
165.5 66.77 107.6
175.71 67.03 105.18
188.17 67.39 112.55
200.42 67.67 110.78
210.45 67.86 107.36
223.27 68.06 101.9
*I thought 3) would have been more onerous than 1), given the coherence exponent and the value of the TI. That was not the case. In general, I thought all cases that included the coherence exponent and TI would be more onerous. *
I have a specific question. Is it the TI, URef and, say wind shear profile (PL or user-defined) and coherence exponent that cause wind conditions to vary? I am trying to understand what wind conditions would cause the most severe response of the wind turbine. From the FF_wind output, the difference in wind conditions was not clear to me.
Sorry for such a long response. I hope I am clearer now.
Regards,
AOAW
Dear @Andre.White,
I see your TurbSim inputs now, but I’m unclear why your Veer angles are so large (between 100 and 140deg)–causing the wind to blow sideways and from behind the rotor (assuming the nacelle-yaw angle is zero).
I’m also not really sure I understand what your question is.
Best regards,
Hi @Jason.Jonkman thank you.
See the veer angles below. I used the values from figure d, the profile highlighted in red. 1) Do my veer angles now make sense
I have also shown as a separate matter the u-component of the wind speed for respective conditions.
Figure 1 – Wind field from TurbSim for the Base Case, showing U-component wind speed, turbulence intensity (TI) = 0, coherence exponent = 0.
Figure 2 – Wind field from TurbSim for the Base Case, showing U-component wind speed, turbulence intensity (TI) = 8.25%, coherence exponent = 0.
Figure 3 – Wind field from TurbSim for the Base Case, showing U-component wind speed, turbulence intensity (TI) = 8.25%, coherence exponent = 0.85.
2)The coherence exponent of 0.85 does not cause any change to the wind filed/ wind loads. Do you believe it is because the value is too low? 3) When TI is used the wind field is coarse, does this mean that it exhibits more onerous wind conditions
For the veer profile the wind loads are negative and relatively smaller. 4) Does this mean that there could be something wrong with my results, say based on veer profile angles that you just mentioned. 5)Also, for veer profile the V-component of the wind speed is the greater than the u-component. I was expecting the u-component to be greater. Could this be a problem with the angles as well?
Figure 4 – Wind field from TurbSim for the Veer Case, showing U-component wind speed, turbulence intensity (TI) = 0%, coherence exponent = 0.
**
Figure 5 – Wind field from TurbSim for the Veer Case, showing U-component wind speed, turbulence intensity (TI) = 8.25 %, coherence exponent = 0.
Figure 6 – Wind field from TurbSim for the Veer Case, showing V-component wind speed, turbulence intensity (TI) = 8.25 %, coherence exponent = 0.
Note that I have raised 5 queries.
Thank you.
Regards,
AOAW
Dear @Andre.White,
Here are my answers to your questions:
-
The problem with your veer angles is that I would expect them to be centered around 0deg near the hub height (because the nacelle-yaw controller will aim for near-zero mean yaw error). Moreover, the frozen turbulence assumption of TurbSim really only works well if the wind direction specified in TurbSim is near zero. So, I would suggest shifting the wind veer angles such that the wind direction at the hub height is zero.
-
I’m not sure. Are you saying you’ve tried different values of the
CohExpand always obtain an identical result? -
We typically recommend using a spatial discretization in TurbSim equal to the maximum chordlength of the blade to obtain converged results from turbulent wind excitation.
-
and 5. Yes; see 1. The veer angle should be near zero at hub height.
Best regards,
Hi @Jason.Jonkman thanks for your response but I need some further clarification.
- For the veer angle, does that mean I need to shift them such that the veer at hub height is 0 and all other angles shown in graph are relative to that. In particular, can I shift all by 130 degrees, say. That shift will make the wind direction at Hub Height 0 degrees instead of 130 deg and other angles will be offset by this 130 deg. Trying to understand how that shift is done.
- Regarding the coherence, would using the von Korman or other model cause the coherence to be taken into consideration.?
Regards,
AOAW
Dear @Andre.White,
Regarding (1), yes, that is what I’m saying.
Regarding (2), I changed my answer to (2) in my post yesterday, which I realized I stated incorrectly. Can you clarify?
Best regards,
Hi @Jason.Jonkman thank you. What I was saying about coherence exponent is that when the value is set to default, that is, zero, I get the same output result as when I change it to 0.85. However, you said that the lines after 43 are not used when Kaimal model is used. The coherence exponent is after this line. Therefore, based on what you have said, I was wondering if this is the reason why I am seeing no changes in the result when the value is changed to 0.85 compared to when it set to default.
I was therefore asking if the von Korman model would read the lines after line 43 and therefore, allow coherence exponent to be considered.
Regards,
AOAW
Dear @Andre.White,
My prior statement was incorrect. It is the “Non-IEC Meteorological Boundary Conditions” and “Coherent Turbulence Scaling Parameters” sections of the TurbSim input file that are not used when either the Kaimal or van Karman spectra are selected. However, the “Spatial Coherence Parameters” section is used regardless. I would expect some difference in the results when CohExp is changed, although the effect may be small.
Best regards,
Noted @Jason.Jonkman. Thank you.
Regards,
AOAW