Tower base loads due wind effect
Moderator: Bonnie.Jonkman

 Posts: 34
 Joined: Mon May 04, 2020 3:31 am
 Organization: Politecnico di Torino
 Location: Italia
Tower base loads due wind effect
Hello everyone,
for my master thesis I developed a model for offshore wind turbines. I just noticed some discrepance between tower base forces calculated with my model and those of FAST v8.16.00abjj.
To solve the problem I tried how these forces are calculated in FAST, but I could not find anything, can you suggest me a document that can help me?
In particular I'm running a Test 18 with:
steady wind of 10 m/s,
all DOF set to "FALSE", except drivetrain and generator DOF;
and the TwrBsFyt has an oscillatory trend, so I can't understand what this force depends on.
Thank you,
Riccardo.
for my master thesis I developed a model for offshore wind turbines. I just noticed some discrepance between tower base forces calculated with my model and those of FAST v8.16.00abjj.
To solve the problem I tried how these forces are calculated in FAST, but I could not find anything, can you suggest me a document that can help me?
In particular I'm running a Test 18 with:
steady wind of 10 m/s,
all DOF set to "FALSE", except drivetrain and generator DOF;
and the TwrBsFyt has an oscillatory trend, so I can't understand what this force depends on.
Thank you,
Riccardo.

 Posts: 5738
 Joined: Thu Nov 03, 2005 4:38 pm
 Location: Boulder, CO
 Contact:
Re: Tower base loads due wind effect
Dear Riccardo,
For information on the FAST theory basis, please see the following forum topic: viewtopic.php?f=4&t=424. That said, much of that doesn't apply when all DOFs are disabled except the drivetrain and generator DOF.
Are you using steady uniform wind without yaw error? Even so, the NREL 5MW turbine has some rotor tilt, which may lead to oscillations in aerodynamic loads. I'd probably have to know more about your simulation setup and results to comment more.
Best regards,
For information on the FAST theory basis, please see the following forum topic: viewtopic.php?f=4&t=424. That said, much of that doesn't apply when all DOFs are disabled except the drivetrain and generator DOF.
Are you using steady uniform wind without yaw error? Even so, the NREL 5MW turbine has some rotor tilt, which may lead to oscillations in aerodynamic loads. I'd probably have to know more about your simulation setup and results to comment more.
Best regards,
Jason Jonkman, Ph.D.
Senior Engineer  National Wind Technology Center (NWTC)
National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway  Golden, CO 80401
+1 (303) 384 – 7026  Fax: +1 (303) 384 – 6901
nwtc.nrel.gov
Senior Engineer  National Wind Technology Center (NWTC)
National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway  Golden, CO 80401
+1 (303) 384 – 7026  Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

 Posts: 34
 Joined: Mon May 04, 2020 3:31 am
 Organization: Politecnico di Torino
 Location: Italia
Re: Tower base loads due wind effect
Dear Jason,
Thanks for your prompt reply. As you requested the results of: TwrBsFxt, TwrBsFyt, TwrBsFzt; are shown in "Force" attachment.
Moreover, the wind trends in each direction are shown in the "Wind" attachment.
While the input files used for this Test are are the follow.
 ELASTODYN v1.03.* INPUT FILE 
NREL 5.0 MW Baseline Wind Turbine for Use in Offshore Analysis. Properties from Dutch Offshore Wind Energy Converter (DOWEC) 6MW PreDesign (10046_009.pdf) and REpower 5M 5MW (5m_uk.pdf)
 SIMULATION CONTROL 
False Echo  Echo input data to "<RootName>.ech" (flag)
3 Method  Integration method: {1: RK4, 2: AB4, or 3: ABM4} ()
"DEFAULT" DT  Integration time step (s)
 ENVIRONMENTAL CONDITION 
9.80665 Gravity  Gravitational acceleration (m/s^2)
 DEGREES OF FREEDOM 
False FlapDOF1  First flapwise blade mode DOF (flag)
False FlapDOF2  Second flapwise blade mode DOF (flag)
False EdgeDOF  First edgewise blade mode DOF (flag)
False TeetDOF  Rotorteeter DOF (flag) [unused for 3 blades]
True DrTrDOF  Drivetrain rotationalflexibility DOF (flag)
True GenDOF  Generator DOF (flag)
False YawDOF  Yaw DOF (flag)
False TwFADOF1  First foreaft tower bendingmode DOF (flag)
False TwFADOF2  Second foreaft tower bendingmode DOF (flag)
False TwSSDOF1  First sidetoside tower bendingmode DOF (flag)
False TwSSDOF2  Second sidetoside tower bendingmode DOF (flag)
False PtfmSgDOF  Platform horizontal surge translation DOF (flag)
False PtfmSwDOF  Platform horizontal sway translation DOF (flag)
False PtfmHvDOF  Platform vertical heave translation DOF (flag)
False PtfmRDOF  Platform roll tilt rotation DOF (flag)
False PtfmPDOF  Platform pitch tilt rotation DOF (flag)
False PtfmYDOF  Platform yaw rotation DOF (flag)
 INITIAL CONDITIONS 
0 OoPDefl  Initial outofplane bladetip displacement (meters)
0 IPDefl  Initial inplane bladetip deflection (meters)
6.364 BlPitch(1)  Blade 1 initial pitch (degrees)
6.364 BlPitch(2)  Blade 2 initial pitch (degrees)
6.364 BlPitch(3)  Blade 3 initial pitch (degrees) [unused for 2 blades]
0 TeetDefl  Initial or fixed teeter angle (degrees) [unused for 3 blades]
0 Azimuth  Initial azimuth angle for blade 1 (degrees)
8.1344 RotSpeed  Initial or fixed rotor speed (rpm)
0 NacYaw  Initial or fixed nacelleyaw angle (degrees)
0 TTDspFA  Initial foreaft towertop displacement (meters)
0 TTDspSS  Initial sidetoside towertop displacement (meters)
0 PtfmSurge  Initial or fixed horizontal surge translational displacement of platform (meters)
0 PtfmSway  Initial or fixed horizontal sway translational displacement of platform (meters)
0 PtfmHeave  Initial or fixed vertical heave translational displacement of platform (meters)
0 PtfmRoll  Initial or fixed roll tilt rotational displacement of platform (degrees)
0 PtfmPitch  Initial or fixed pitch tilt rotational displacement of platform (degrees)
0 PtfmYaw  Initial or fixed yaw rotational displacement of platform (degrees)
 TURBINE CONFIGURATION 
3 NumBl  Number of blades ()
63 TipRad  The distance from the rotor apex to the blade tip (meters)
1.5 HubRad  The distance from the rotor apex to the blade root (meters)
0 PreCone(1)  Blade 1 cone angle (degrees)
0 PreCone(2)  Blade 2 cone angle (degrees)
0 PreCone(3)  Blade 3 cone angle (degrees) [unused for 2 blades]
0 HubCM  Distance from rotor apex to hub mass [positive downwind] (meters)
0 UndSling  Undersling length [distance from teeter pin to the rotor apex] (meters) [unused for 3 blades]
0 Delta3  Delta3 angle for teetering rotors (degrees) [unused for 3 blades]
0 AzimB1Up  Azimuth value to use for I/O when blade 1 points up (degrees)
5 OverHang  Distance from yaw axis to rotor apex [3 blades] or teeter pin [2 blades] (meters)
1.912 ShftGagL  Distance from rotor apex [3 blades] or teeter pin [2 blades] to shaft strain gages [positive for upwind rotors] (meters)
0 ShftTilt  Rotor shaft tilt angle (degrees)
1.9 NacCMxn  Downwind distance from the towertop to the nacelle CM (meters)
0 NacCMyn  Lateral distance from the towertop to the nacelle CM (meters)
1.75 NacCMzn  Vertical distance from the towertop to the nacelle CM (meters)
3.09528 NcIMUxn  Downwind distance from the towertop to the nacelle IMU (meters)
0 NcIMUyn  Lateral distance from the towertop to the nacelle IMU (meters)
2.23336 NcIMUzn  Vertical distance from the towertop to the nacelle IMU (meters)
2 Twr2Shft  Vertical distance from the towertop to the rotor shaft (meters)
87.6 TowerHt  Height of tower above ground level [onshore] or MSL [offshore] (meters)
0 TowerBsHt  Height of tower base above ground level [onshore] or MSL [offshore] (meters)
0 PtfmCMxt  Downwind distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters)
0 PtfmCMyt  Lateral distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters)
0 PtfmCMzt  Vertical distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters)
0 PtfmRefzt  Vertical distance from the ground level [onshore] or MSL [offshore] to the platform reference point (meters)
 MASS AND INERTIA 
0 TipMass(1)  Tipbrake mass, blade 1 (kg)
0 TipMass(2)  Tipbrake mass, blade 2 (kg)
0 TipMass(3)  Tipbrake mass, blade 3 (kg) [unused for 2 blades]
56780 HubMass  Hub mass (kg)
115926 HubIner  Hub inertia about rotor axis [3 blades] or teeter axis [2 blades] (kg m^2)
534.116 GenIner  Generator inertia about HSS (kg m^2)
240000 NacMass  Nacelle mass (kg)
2.60789E+06 NacYIner  Nacelle inertia about yaw axis (kg m^2)
0 YawBrMass  Yaw bearing mass (kg)
0 PtfmMass  Platform mass (kg)
0 PtfmRIner  Platform inertia for roll tilt rotation about the platform CM (kg m^2)
0 PtfmPIner  Platform inertia for pitch tilt rotation about the platform CM (kg m^2)
0 PtfmYIner  Platform inertia for yaw rotation about the platform CM (kg m^2)
 BLADE 
17 BldNodes  Number of blade nodes (per blade) used for analysis ()
"NRELOffshrBsline5MW_Blade.dat" BldFile(1)  Name of file containing properties for blade 1 (quoted string)
"NRELOffshrBsline5MW_Blade.dat" BldFile(2)  Name of file containing properties for blade 2 (quoted string)
"NRELOffshrBsline5MW_Blade.dat" BldFile(3)  Name of file containing properties for blade 3 (quoted string) [unused for 2 blades]
 ROTORTEETER 
0 TeetMod  Rotorteeter spring/damper model {0: none, 1: standard, 2: userdefined from routine UserTeet} (switch) [unused for 3 blades]
0 TeetDmpP  Rotorteeter damper position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetDmp  Rotorteeter damping constant (Nm/(rad/s)) [used only for 2 blades and when TeetMod=1]
0 TeetCDmp  Rotorteeter rateindependent Coulombdamping moment (Nm) [used only for 2 blades and when TeetMod=1]
0 TeetSStP  Rotorteeter softstop position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetHStP  Rotorteeter hardstop position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetSSSp  Rotorteeter softstop linearspring constant (Nm/rad) [used only for 2 blades and when TeetMod=1]
0 TeetHSSp  Rotorteeter hardstop linearspring constant (Nm/rad) [used only for 2 blades and when TeetMod=1]
 DRIVETRAIN 
100 GBoxEff  Gearbox efficiency (%)
97 GBRatio  Gearbox ratio ()
8.67637E+08 DTTorSpr  Drivetrain torsional spring (Nm/rad)
5.900E+06 DTTorDmp  Drivetrain torsional damper (Nm/(rad/s))
 FURLING 
False Furling  Read in additional model properties for furling turbine (flag) [must currently be FALSE)
"unused" FurlFile  Name of file containing furling properties (quoted string) [unused when Furling=False]
 TOWER 
20 TwrNodes  Number of tower nodes used for analysis ()
"NRELOffshrBsline5MW_Onshore_ElastoDyn_Tower.dat" TwrFile  Name of file containing tower properties (quoted string)
 OUTPUT 
True SumPrint  Print summary data to "<RootName>.sum" (flag)
1 OutFile  Switch to determine where output will be placed: {1: in module output file only; 2: in glue code output file only; 3: both} (currently unused)
True TabDelim  Use tab delimiters in text tabular output file? (flag) (currently unused)
"ES10.3E2" OutFmt  Format used for text tabular output (except time). Resulting field should be 10 characters. (quoted string) (currently unused)
0 TStart  Time to begin tabular output (s) (currently unused)
1 DecFact  Decimation factor for tabular output {1: output every time step} () (currently unused)
0 NTwGages  Number of tower nodes that have strain gages for output [0 to 9] ()
10, 19, 28 TwrGagNd  List of tower nodes that have strain gages [1 to TwrNodes] () [unused if NTwGages=0]
3 NBlGages  Number of blade nodes that have strain gages for output [0 to 9] ()
5, 9, 13 BldGagNd  List of blade nodes that have strain gages [1 to BldNodes] () [unused if NBlGages=0]
OutList  The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, ()
"OoPDefl1"  Blade 1 outofplane and inplane deflections and tip twist
"IPDefl1"  Blade 1 outofplane and inplane deflections and tip twist
"TwstDefl1"  Blade 1 outofplane and inplane deflections and tip twist
"BldPitch1"  Blade 1 pitch angle
"Azimuth"  Blade 1 azimuth angle
"RotSpeed"  Lowspeed shaft and highspeed shaft speeds
"GenSpeed"  Lowspeed shaft and highspeed shaft speeds
"TTDspFA"  Tower foreaft and sidetoside displacements and top twist
"TTDspSS"  Tower foreaft and sidetoside displacements and top twist
"TTDspTwst"  Tower foreaft and sidetoside displacements and top twist
"NacYaw"  Nacelle yaw angle and nacelle yaw error estimate
"RootFxb1"  Outofplane shear, inplane shear, and axial forces at the root of blade 1
"RootFyb1"  Outofplane shear, inplane shear, and axial forces at the root of blade 1
"RootFzb1"  Outofplane shear, inplane shear, and axial forces at the root of blade 1
"RootMxb1"  Inplane bending, outofplane bending, and pitching moments at the root of blade 1
"RootMyb1"  Inplane bending, outofplane bending, and pitching moments at the root of blade 1
"RootMzb1"  Inplane bending, outofplane bending, and pitching moments at the root of blade 1
"RotTorq"  Rotor torque and lowspeed shaft 0 and 90bending moments at the main bearing
"RotThrust"
"YawBrFxp"  Foreaft shear, sidetoside shear, and vertical forces at the top of the tower (not rotating with nacelle yaw)
"YawBrFyp"  Foreaft shear, sidetoside shear, and vertical forces at the top of the tower (not rotating with nacelle yaw)
"YawBrFzp"  Foreaft shear, sidetoside shear, and vertical forces at the top of the tower (not rotating with nacelle yaw)
"YawBrMxp"  Sidetoside bending, foreaft bending, and yaw moments at the top of the tower (not rotating with nacelle yaw)
"YawBrMyp"  Sidetoside bending, foreaft bending, and yaw moments at the top of the tower (not rotating with nacelle yaw)
"YawBrMzp"  Sidetoside bending, foreaft bending, and yaw moments at the top of the tower (not rotating with nacelle yaw)
"TwrBsFxt"  Foreaft shear, sidetoside shear, and vertical forces at the base of the tower (mudline)
"TwrBsFyt"  Foreaft shear, sidetoside shear, and vertical forces at the base of the tower (mudline)
"TwrBsFzt"  Foreaft shear, sidetoside shear, and vertical forces at the base of the tower (mudline)
"TwrBsMxt"  Sidetoside bending, foreaft bending, and yaw moments at the base of the tower (mudline)
"TwrBsMyt"  Sidetoside bending, foreaft bending, and yaw moments at the base of the tower (mudline)
"TwrBsMzt"  Sidetoside bending, foreaft bending, and yaw moments at the base of the tower (mudline)
END of input file (the word "END" must appear in the first 3 columns of this last OutList line)

 InflowWind v3.01.* INPUT FILE 
12 m/s turbulent winds on 31x31 FF grid and tower for FAST CertTests #18, #19, #21, #22, #23, and #24

False Echo  Echo input data to <RootName>.ech (flag)
1 WindType  switch for wind file type (1=steady; 2=uniform; 3=binary TurbSim FF; 4=binary Bladedstyle FF; 5=HAWC format; 6=User defined)
0 PropagationDir  Direction of wind propagation (meteoroligical rotation from aligned with X (positive rotates towards Y)  degrees)
1 NWindVel  Number of points to output the wind velocity (0 to 9)
0 WindVxiList  List of coordinates in the inertial X direction (m)
0 WindVyiList  List of coordinates in the inertial Y direction (m)
90 WindVziList  List of coordinates in the inertial Z direction (m)
================== Parameters for Steady Wind Conditions [used only for WindType = 1] =========================
10 HWindSpeed  Horizontal windspeed (m/s)
90 RefHt  Reference height for horizontal wind speed (m)
0.2 PLexp  Power law exponent ()
================== Parameters for Uniform wind file [used only for WindType = 2] ============================
"Wind/90m_12mps_twr.bin" Filename  Filename of time series data for uniform wind field. ()
90 RefHt  Reference height for horizontal wind speed (m)
125.88 RefLength  Reference length for linear horizontal and vertical sheer ()
================== Parameters for Binary TurbSim FullField files [used only for WindType = 3] ==============
"Wind/Wind_NTM_B_13_v0h0.bts" Filename  Name of the Full field wind file to use (.bts)
================== Parameters for Binary Bladedstyle FullField files [used only for WindType = 4] =========
"Wind/90m_12mps_twr" FilenameRoot  Rootname of the fullfield wind file to use (.wnd, .sum)
False TowerFile  Have tower file (.twr) (flag)
================== Parameters for HAWCformat binary files [Only used with WindType = 5] =====================
"wasp\Output\basic_5u.bin" FileName_u  name of the file containing the ucomponent fluctuating wind (.bin)
"wasp\Output\basic_5v.bin" FileName_v  name of the file containing the vcomponent fluctuating wind (.bin)
"wasp\Output\basic_5w.bin" FileName_w  name of the file containing the wcomponent fluctuating wind (.bin)
64 nx  number of grids in the x direction (in the 3 files above) ()
32 ny  number of grids in the y direction (in the 3 files above) ()
32 nz  number of grids in the z direction (in the 3 files above) ()
16 dx  distance (in meters) between points in the x direction (m)
3 dy  distance (in meters) between points in the y direction (m)
3 dz  distance (in meters) between points in the z direction (m)
90 RefHt  reference height; the height (in meters) of the vertical center of the grid (m)
 Scaling parameters for turbulence 
1 ScaleMethod  Turbulence scaling method [0 = none, 1 = direct scaling, 2 = calculate scaling factor based on a desired standard deviation]
1 SFx  Turbulence scaling factor for the x direction () [ScaleMethod=1]
1 SFy  Turbulence scaling factor for the y direction () [ScaleMethod=1]
1 SFz  Turbulence scaling factor for the z direction () [ScaleMethod=1]
12 SigmaFx  Turbulence standard deviation to calculate scaling from in x direction (m/s) [ScaleMethod=2]
8 SigmaFy  Turbulence standard deviation to calculate scaling from in y direction (m/s) [ScaleMethod=2]
2 SigmaFz  Turbulence standard deviation to calculate scaling from in z direction (m/s) [ScaleMethod=2]
 Mean wind profile parameters (added to HAWCformat files) 
10.151 URef  Mean ucomponent wind speed at the reference height (m/s)
0 WindProfile  Wind profile type (0=constant;1=logarithmic,2=power law)
0.2 PLExp  Power law exponent () (used for PL wind profile type only)
0.03 Z0  Surface roughness length (m) (used for LG wind profile type only)
====================== OUTPUT ==================================================
False SumPrint  Print summary data to <RootName>.IfW.sum (flag)
OutList  The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, ()
"Wind1VelX" Xdirection wind velocity at point WindList(1)
"Wind1VelY" Ydirection wind velocity at point WindList(1)
"Wind1VelZ" Zdirection wind velocity at point WindList(1)
END of input file (the word "END" must appear in the first 3 columns of this last OutList line)

 AERODYN v15.03.* INPUT FILE 
NREL 5.0 MW offshore baseline aerodynamic input properties.
====== General Options ============================================================================
False Echo  Echo the input to "<rootname>.AD.ech"? (flag)
"default" DTAero  Time interval for aerodynamic calculations {or "default"} (s)
1 WakeMod  Type of wake/induction model (switch) {0=none, 1=BEMT}
1 AFAeroMod  Type of blade airfoil aerodynamics model (switch) {1=steady model, 2=BeddoesLeishman unsteady model}
0 TwrPotent  Type tower influence on wind based on potential flow around the tower (switch) {0=none, 1=baseline potential flow, 2=potential flow with Bak correction}
False TwrShadow – Calculate tower influence on wind based on downstream tower shadow? (flag)
False TwrAero  Calculate tower aerodynamic loads? (flag)
False FrozenWake  Assume frozen wake during linearization? (flag) [used only when WakeMod=1 and when linearizing]
====== Environmental Conditions ===================================================================
1.2 AirDens  Air density (kg/m^3)
1.464E05 KinVisc  Kinematic air viscosity (m^2/s)
335 SpdSound  Speed of sound (m/s)
====== BladeElement/Momentum Theory Options ====================================================== [used only when WakeMod=1]
2 SkewMod  Type of skewedwake correction model (switch) {1=uncoupled, 2=Pitt/Peters, 3=coupled} [used only when WakeMod=1]
True TipLoss  Use the Prandtl tiploss model? (flag) [used only when WakeMod=1]
True HubLoss  Use the Prandtl hubloss model? (flag) [used only when WakeMod=1]
True TanInd  Include tangential induction in BEMT calculations? (flag) [used only when WakeMod=1]
True AIDrag  Include the drag term in the axialinduction calculation? (flag) [used only when WakeMod=1]
True TIDrag  Include the drag term in the tangentialinduction calculation? (flag) [used only when WakeMod=1 and TanInd=TRUE]
"Default" IndToler  Convergence tolerance for BEMT nonlinear solve residual equation {or "default"} () [used only when WakeMod=1]
100 MaxIter  Maximum number of iteration steps () [used only when WakeMod=1]
====== BeddoesLeishman Unsteady Airfoil Aerodynamics Options ===================================== [used only when AFAeroMod=2]
3 UAMod  Unsteady Aero Model Switch (switch) {1=Baseline model (Original), 2=Gonzalez’s variant (changes in Cn,Cc,Cm), 3=Minemma/Pierce variant (changes in Cc and Cm)} [used only when AFAeroMod=2]
True FLookup  Flag to indicate whether a lookup for f' will be calculated (TRUE) or whether bestfit exponential equations will be used (FALSE); if FALSE S1S4 must be provided in airfoil input files (flag) [used only when AFAeroMod=2]
====== Airfoil Information =========================================================================
1 InCol_Alfa  The column in the airfoil tables that contains the angle of attack ()
2 InCol_Cl  The column in the airfoil tables that contains the lift coefficient ()
3 InCol_Cd  The column in the airfoil tables that contains the drag coefficient ()
4 InCol_Cm  The column in the airfoil tables that contains the pitchingmoment coefficient; use zero if there is no Cm column ()
0 InCol_Cpmin  The column in the airfoil tables that contains the Cpmin coefficient; use zero if there is no Cpmin column ()
8 NumAFfiles  Number of airfoil files used ()
"Airfoils/Cylinder1.dat" AFNames  Airfoil file names (NumAFfiles lines) (quoted strings)
"Airfoils/Cylinder2.dat"
"Airfoils/DU40_A17.dat"
"Airfoils/DU35_A17.dat"
"Airfoils/DU30_A17.dat"
"Airfoils/DU25_A17.dat"
"Airfoils/DU21_A17.dat"
"Airfoils/NACA64_A17.dat"
====== Rotor/Blade Properties =====================================================================
True UseBlCm  Include aerodynamic pitching moment in calculations? (flag)
"NRELOffshrBsline5MW_AeroDyn_blade.dat" ADBlFile(1)  Name of file containing distributed aerodynamic properties for Blade #1 ()
"NRELOffshrBsline5MW_AeroDyn_blade.dat" ADBlFile(2)  Name of file containing distributed aerodynamic properties for Blade #2 () [unused if NumBl < 2]
"NRELOffshrBsline5MW_AeroDyn_blade.dat" ADBlFile(3)  Name of file containing distributed aerodynamic properties for Blade #3 () [unused if NumBl < 3]
====== Tower Influence and Aerodynamics ============================================================= [used only when TwrPotent/=0, TwrShadow=True, or TwrAero=True]
12 NumTwrNds  Number of tower nodes used in the analysis () [used only when TwrPotent/=0, TwrShadow=True, or TwrAero=True]
TwrElev TwrDiam TwrCd
(m) (m) ()
0.0000000E+00 6.0000000E+00 1.0000000E+00
8.5261000E+00 5.7870000E+00 1.0000000E+00
1.7053000E+01 5.5740000E+00 1.0000000E+00
2.5579000E+01 5.3610000E+00 1.0000000E+00
3.4105000E+01 5.1480000E+00 1.0000000E+00
4.2633000E+01 4.9350000E+00 1.0000000E+00
5.1158000E+01 4.7220000E+00 1.0000000E+00
5.9685000E+01 4.5090000E+00 1.0000000E+00
6.8211000E+01 4.2960000E+00 1.0000000E+00
7.6738000E+01 4.0830000E+00 1.0000000E+00
8.5268000E+01 3.8700000E+00 1.0000000E+00
8.7600000E+01 3.8700000E+00 1.0000000E+00
====== Outputs ====================================================================================
True SumPrint  Generate a summary file listing input options and interpolated properties to "<rootname>.AD.sum"? (flag)
0 NBlOuts  Number of blade node outputs [0  9] ()
1, 9, 19 BlOutNd  Blade nodes whose values will be output ()
0 NTwOuts  Number of tower node outputs [0  9] ()
1, 2, 6 TwOutNd  Tower nodes whose values will be output ()
OutList  The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, ()
"RtAeroFxh"
"RtAeroFyh"
"RtAeroFzh"
"RtAeroMxh"
"RtAeroMyh"
"RtAeroMzh"
"RtAeroPwr"
END of input file (the word "END" must appear in the first 3 columns of this last OutList line)

Thank you for your help.
Best regards,
Riccardo.
Thanks for your prompt reply. As you requested the results of: TwrBsFxt, TwrBsFyt, TwrBsFzt; are shown in "Force" attachment.
Moreover, the wind trends in each direction are shown in the "Wind" attachment.
While the input files used for this Test are are the follow.
 ELASTODYN v1.03.* INPUT FILE 
NREL 5.0 MW Baseline Wind Turbine for Use in Offshore Analysis. Properties from Dutch Offshore Wind Energy Converter (DOWEC) 6MW PreDesign (10046_009.pdf) and REpower 5M 5MW (5m_uk.pdf)
 SIMULATION CONTROL 
False Echo  Echo input data to "<RootName>.ech" (flag)
3 Method  Integration method: {1: RK4, 2: AB4, or 3: ABM4} ()
"DEFAULT" DT  Integration time step (s)
 ENVIRONMENTAL CONDITION 
9.80665 Gravity  Gravitational acceleration (m/s^2)
 DEGREES OF FREEDOM 
False FlapDOF1  First flapwise blade mode DOF (flag)
False FlapDOF2  Second flapwise blade mode DOF (flag)
False EdgeDOF  First edgewise blade mode DOF (flag)
False TeetDOF  Rotorteeter DOF (flag) [unused for 3 blades]
True DrTrDOF  Drivetrain rotationalflexibility DOF (flag)
True GenDOF  Generator DOF (flag)
False YawDOF  Yaw DOF (flag)
False TwFADOF1  First foreaft tower bendingmode DOF (flag)
False TwFADOF2  Second foreaft tower bendingmode DOF (flag)
False TwSSDOF1  First sidetoside tower bendingmode DOF (flag)
False TwSSDOF2  Second sidetoside tower bendingmode DOF (flag)
False PtfmSgDOF  Platform horizontal surge translation DOF (flag)
False PtfmSwDOF  Platform horizontal sway translation DOF (flag)
False PtfmHvDOF  Platform vertical heave translation DOF (flag)
False PtfmRDOF  Platform roll tilt rotation DOF (flag)
False PtfmPDOF  Platform pitch tilt rotation DOF (flag)
False PtfmYDOF  Platform yaw rotation DOF (flag)
 INITIAL CONDITIONS 
0 OoPDefl  Initial outofplane bladetip displacement (meters)
0 IPDefl  Initial inplane bladetip deflection (meters)
6.364 BlPitch(1)  Blade 1 initial pitch (degrees)
6.364 BlPitch(2)  Blade 2 initial pitch (degrees)
6.364 BlPitch(3)  Blade 3 initial pitch (degrees) [unused for 2 blades]
0 TeetDefl  Initial or fixed teeter angle (degrees) [unused for 3 blades]
0 Azimuth  Initial azimuth angle for blade 1 (degrees)
8.1344 RotSpeed  Initial or fixed rotor speed (rpm)
0 NacYaw  Initial or fixed nacelleyaw angle (degrees)
0 TTDspFA  Initial foreaft towertop displacement (meters)
0 TTDspSS  Initial sidetoside towertop displacement (meters)
0 PtfmSurge  Initial or fixed horizontal surge translational displacement of platform (meters)
0 PtfmSway  Initial or fixed horizontal sway translational displacement of platform (meters)
0 PtfmHeave  Initial or fixed vertical heave translational displacement of platform (meters)
0 PtfmRoll  Initial or fixed roll tilt rotational displacement of platform (degrees)
0 PtfmPitch  Initial or fixed pitch tilt rotational displacement of platform (degrees)
0 PtfmYaw  Initial or fixed yaw rotational displacement of platform (degrees)
 TURBINE CONFIGURATION 
3 NumBl  Number of blades ()
63 TipRad  The distance from the rotor apex to the blade tip (meters)
1.5 HubRad  The distance from the rotor apex to the blade root (meters)
0 PreCone(1)  Blade 1 cone angle (degrees)
0 PreCone(2)  Blade 2 cone angle (degrees)
0 PreCone(3)  Blade 3 cone angle (degrees) [unused for 2 blades]
0 HubCM  Distance from rotor apex to hub mass [positive downwind] (meters)
0 UndSling  Undersling length [distance from teeter pin to the rotor apex] (meters) [unused for 3 blades]
0 Delta3  Delta3 angle for teetering rotors (degrees) [unused for 3 blades]
0 AzimB1Up  Azimuth value to use for I/O when blade 1 points up (degrees)
5 OverHang  Distance from yaw axis to rotor apex [3 blades] or teeter pin [2 blades] (meters)
1.912 ShftGagL  Distance from rotor apex [3 blades] or teeter pin [2 blades] to shaft strain gages [positive for upwind rotors] (meters)
0 ShftTilt  Rotor shaft tilt angle (degrees)
1.9 NacCMxn  Downwind distance from the towertop to the nacelle CM (meters)
0 NacCMyn  Lateral distance from the towertop to the nacelle CM (meters)
1.75 NacCMzn  Vertical distance from the towertop to the nacelle CM (meters)
3.09528 NcIMUxn  Downwind distance from the towertop to the nacelle IMU (meters)
0 NcIMUyn  Lateral distance from the towertop to the nacelle IMU (meters)
2.23336 NcIMUzn  Vertical distance from the towertop to the nacelle IMU (meters)
2 Twr2Shft  Vertical distance from the towertop to the rotor shaft (meters)
87.6 TowerHt  Height of tower above ground level [onshore] or MSL [offshore] (meters)
0 TowerBsHt  Height of tower base above ground level [onshore] or MSL [offshore] (meters)
0 PtfmCMxt  Downwind distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters)
0 PtfmCMyt  Lateral distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters)
0 PtfmCMzt  Vertical distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters)
0 PtfmRefzt  Vertical distance from the ground level [onshore] or MSL [offshore] to the platform reference point (meters)
 MASS AND INERTIA 
0 TipMass(1)  Tipbrake mass, blade 1 (kg)
0 TipMass(2)  Tipbrake mass, blade 2 (kg)
0 TipMass(3)  Tipbrake mass, blade 3 (kg) [unused for 2 blades]
56780 HubMass  Hub mass (kg)
115926 HubIner  Hub inertia about rotor axis [3 blades] or teeter axis [2 blades] (kg m^2)
534.116 GenIner  Generator inertia about HSS (kg m^2)
240000 NacMass  Nacelle mass (kg)
2.60789E+06 NacYIner  Nacelle inertia about yaw axis (kg m^2)
0 YawBrMass  Yaw bearing mass (kg)
0 PtfmMass  Platform mass (kg)
0 PtfmRIner  Platform inertia for roll tilt rotation about the platform CM (kg m^2)
0 PtfmPIner  Platform inertia for pitch tilt rotation about the platform CM (kg m^2)
0 PtfmYIner  Platform inertia for yaw rotation about the platform CM (kg m^2)
 BLADE 
17 BldNodes  Number of blade nodes (per blade) used for analysis ()
"NRELOffshrBsline5MW_Blade.dat" BldFile(1)  Name of file containing properties for blade 1 (quoted string)
"NRELOffshrBsline5MW_Blade.dat" BldFile(2)  Name of file containing properties for blade 2 (quoted string)
"NRELOffshrBsline5MW_Blade.dat" BldFile(3)  Name of file containing properties for blade 3 (quoted string) [unused for 2 blades]
 ROTORTEETER 
0 TeetMod  Rotorteeter spring/damper model {0: none, 1: standard, 2: userdefined from routine UserTeet} (switch) [unused for 3 blades]
0 TeetDmpP  Rotorteeter damper position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetDmp  Rotorteeter damping constant (Nm/(rad/s)) [used only for 2 blades and when TeetMod=1]
0 TeetCDmp  Rotorteeter rateindependent Coulombdamping moment (Nm) [used only for 2 blades and when TeetMod=1]
0 TeetSStP  Rotorteeter softstop position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetHStP  Rotorteeter hardstop position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetSSSp  Rotorteeter softstop linearspring constant (Nm/rad) [used only for 2 blades and when TeetMod=1]
0 TeetHSSp  Rotorteeter hardstop linearspring constant (Nm/rad) [used only for 2 blades and when TeetMod=1]
 DRIVETRAIN 
100 GBoxEff  Gearbox efficiency (%)
97 GBRatio  Gearbox ratio ()
8.67637E+08 DTTorSpr  Drivetrain torsional spring (Nm/rad)
5.900E+06 DTTorDmp  Drivetrain torsional damper (Nm/(rad/s))
 FURLING 
False Furling  Read in additional model properties for furling turbine (flag) [must currently be FALSE)
"unused" FurlFile  Name of file containing furling properties (quoted string) [unused when Furling=False]
 TOWER 
20 TwrNodes  Number of tower nodes used for analysis ()
"NRELOffshrBsline5MW_Onshore_ElastoDyn_Tower.dat" TwrFile  Name of file containing tower properties (quoted string)
 OUTPUT 
True SumPrint  Print summary data to "<RootName>.sum" (flag)
1 OutFile  Switch to determine where output will be placed: {1: in module output file only; 2: in glue code output file only; 3: both} (currently unused)
True TabDelim  Use tab delimiters in text tabular output file? (flag) (currently unused)
"ES10.3E2" OutFmt  Format used for text tabular output (except time). Resulting field should be 10 characters. (quoted string) (currently unused)
0 TStart  Time to begin tabular output (s) (currently unused)
1 DecFact  Decimation factor for tabular output {1: output every time step} () (currently unused)
0 NTwGages  Number of tower nodes that have strain gages for output [0 to 9] ()
10, 19, 28 TwrGagNd  List of tower nodes that have strain gages [1 to TwrNodes] () [unused if NTwGages=0]
3 NBlGages  Number of blade nodes that have strain gages for output [0 to 9] ()
5, 9, 13 BldGagNd  List of blade nodes that have strain gages [1 to BldNodes] () [unused if NBlGages=0]
OutList  The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, ()
"OoPDefl1"  Blade 1 outofplane and inplane deflections and tip twist
"IPDefl1"  Blade 1 outofplane and inplane deflections and tip twist
"TwstDefl1"  Blade 1 outofplane and inplane deflections and tip twist
"BldPitch1"  Blade 1 pitch angle
"Azimuth"  Blade 1 azimuth angle
"RotSpeed"  Lowspeed shaft and highspeed shaft speeds
"GenSpeed"  Lowspeed shaft and highspeed shaft speeds
"TTDspFA"  Tower foreaft and sidetoside displacements and top twist
"TTDspSS"  Tower foreaft and sidetoside displacements and top twist
"TTDspTwst"  Tower foreaft and sidetoside displacements and top twist
"NacYaw"  Nacelle yaw angle and nacelle yaw error estimate
"RootFxb1"  Outofplane shear, inplane shear, and axial forces at the root of blade 1
"RootFyb1"  Outofplane shear, inplane shear, and axial forces at the root of blade 1
"RootFzb1"  Outofplane shear, inplane shear, and axial forces at the root of blade 1
"RootMxb1"  Inplane bending, outofplane bending, and pitching moments at the root of blade 1
"RootMyb1"  Inplane bending, outofplane bending, and pitching moments at the root of blade 1
"RootMzb1"  Inplane bending, outofplane bending, and pitching moments at the root of blade 1
"RotTorq"  Rotor torque and lowspeed shaft 0 and 90bending moments at the main bearing
"RotThrust"
"YawBrFxp"  Foreaft shear, sidetoside shear, and vertical forces at the top of the tower (not rotating with nacelle yaw)
"YawBrFyp"  Foreaft shear, sidetoside shear, and vertical forces at the top of the tower (not rotating with nacelle yaw)
"YawBrFzp"  Foreaft shear, sidetoside shear, and vertical forces at the top of the tower (not rotating with nacelle yaw)
"YawBrMxp"  Sidetoside bending, foreaft bending, and yaw moments at the top of the tower (not rotating with nacelle yaw)
"YawBrMyp"  Sidetoside bending, foreaft bending, and yaw moments at the top of the tower (not rotating with nacelle yaw)
"YawBrMzp"  Sidetoside bending, foreaft bending, and yaw moments at the top of the tower (not rotating with nacelle yaw)
"TwrBsFxt"  Foreaft shear, sidetoside shear, and vertical forces at the base of the tower (mudline)
"TwrBsFyt"  Foreaft shear, sidetoside shear, and vertical forces at the base of the tower (mudline)
"TwrBsFzt"  Foreaft shear, sidetoside shear, and vertical forces at the base of the tower (mudline)
"TwrBsMxt"  Sidetoside bending, foreaft bending, and yaw moments at the base of the tower (mudline)
"TwrBsMyt"  Sidetoside bending, foreaft bending, and yaw moments at the base of the tower (mudline)
"TwrBsMzt"  Sidetoside bending, foreaft bending, and yaw moments at the base of the tower (mudline)
END of input file (the word "END" must appear in the first 3 columns of this last OutList line)

 InflowWind v3.01.* INPUT FILE 
12 m/s turbulent winds on 31x31 FF grid and tower for FAST CertTests #18, #19, #21, #22, #23, and #24

False Echo  Echo input data to <RootName>.ech (flag)
1 WindType  switch for wind file type (1=steady; 2=uniform; 3=binary TurbSim FF; 4=binary Bladedstyle FF; 5=HAWC format; 6=User defined)
0 PropagationDir  Direction of wind propagation (meteoroligical rotation from aligned with X (positive rotates towards Y)  degrees)
1 NWindVel  Number of points to output the wind velocity (0 to 9)
0 WindVxiList  List of coordinates in the inertial X direction (m)
0 WindVyiList  List of coordinates in the inertial Y direction (m)
90 WindVziList  List of coordinates in the inertial Z direction (m)
================== Parameters for Steady Wind Conditions [used only for WindType = 1] =========================
10 HWindSpeed  Horizontal windspeed (m/s)
90 RefHt  Reference height for horizontal wind speed (m)
0.2 PLexp  Power law exponent ()
================== Parameters for Uniform wind file [used only for WindType = 2] ============================
"Wind/90m_12mps_twr.bin" Filename  Filename of time series data for uniform wind field. ()
90 RefHt  Reference height for horizontal wind speed (m)
125.88 RefLength  Reference length for linear horizontal and vertical sheer ()
================== Parameters for Binary TurbSim FullField files [used only for WindType = 3] ==============
"Wind/Wind_NTM_B_13_v0h0.bts" Filename  Name of the Full field wind file to use (.bts)
================== Parameters for Binary Bladedstyle FullField files [used only for WindType = 4] =========
"Wind/90m_12mps_twr" FilenameRoot  Rootname of the fullfield wind file to use (.wnd, .sum)
False TowerFile  Have tower file (.twr) (flag)
================== Parameters for HAWCformat binary files [Only used with WindType = 5] =====================
"wasp\Output\basic_5u.bin" FileName_u  name of the file containing the ucomponent fluctuating wind (.bin)
"wasp\Output\basic_5v.bin" FileName_v  name of the file containing the vcomponent fluctuating wind (.bin)
"wasp\Output\basic_5w.bin" FileName_w  name of the file containing the wcomponent fluctuating wind (.bin)
64 nx  number of grids in the x direction (in the 3 files above) ()
32 ny  number of grids in the y direction (in the 3 files above) ()
32 nz  number of grids in the z direction (in the 3 files above) ()
16 dx  distance (in meters) between points in the x direction (m)
3 dy  distance (in meters) between points in the y direction (m)
3 dz  distance (in meters) between points in the z direction (m)
90 RefHt  reference height; the height (in meters) of the vertical center of the grid (m)
 Scaling parameters for turbulence 
1 ScaleMethod  Turbulence scaling method [0 = none, 1 = direct scaling, 2 = calculate scaling factor based on a desired standard deviation]
1 SFx  Turbulence scaling factor for the x direction () [ScaleMethod=1]
1 SFy  Turbulence scaling factor for the y direction () [ScaleMethod=1]
1 SFz  Turbulence scaling factor for the z direction () [ScaleMethod=1]
12 SigmaFx  Turbulence standard deviation to calculate scaling from in x direction (m/s) [ScaleMethod=2]
8 SigmaFy  Turbulence standard deviation to calculate scaling from in y direction (m/s) [ScaleMethod=2]
2 SigmaFz  Turbulence standard deviation to calculate scaling from in z direction (m/s) [ScaleMethod=2]
 Mean wind profile parameters (added to HAWCformat files) 
10.151 URef  Mean ucomponent wind speed at the reference height (m/s)
0 WindProfile  Wind profile type (0=constant;1=logarithmic,2=power law)
0.2 PLExp  Power law exponent () (used for PL wind profile type only)
0.03 Z0  Surface roughness length (m) (used for LG wind profile type only)
====================== OUTPUT ==================================================
False SumPrint  Print summary data to <RootName>.IfW.sum (flag)
OutList  The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, ()
"Wind1VelX" Xdirection wind velocity at point WindList(1)
"Wind1VelY" Ydirection wind velocity at point WindList(1)
"Wind1VelZ" Zdirection wind velocity at point WindList(1)
END of input file (the word "END" must appear in the first 3 columns of this last OutList line)

 AERODYN v15.03.* INPUT FILE 
NREL 5.0 MW offshore baseline aerodynamic input properties.
====== General Options ============================================================================
False Echo  Echo the input to "<rootname>.AD.ech"? (flag)
"default" DTAero  Time interval for aerodynamic calculations {or "default"} (s)
1 WakeMod  Type of wake/induction model (switch) {0=none, 1=BEMT}
1 AFAeroMod  Type of blade airfoil aerodynamics model (switch) {1=steady model, 2=BeddoesLeishman unsteady model}
0 TwrPotent  Type tower influence on wind based on potential flow around the tower (switch) {0=none, 1=baseline potential flow, 2=potential flow with Bak correction}
False TwrShadow – Calculate tower influence on wind based on downstream tower shadow? (flag)
False TwrAero  Calculate tower aerodynamic loads? (flag)
False FrozenWake  Assume frozen wake during linearization? (flag) [used only when WakeMod=1 and when linearizing]
====== Environmental Conditions ===================================================================
1.2 AirDens  Air density (kg/m^3)
1.464E05 KinVisc  Kinematic air viscosity (m^2/s)
335 SpdSound  Speed of sound (m/s)
====== BladeElement/Momentum Theory Options ====================================================== [used only when WakeMod=1]
2 SkewMod  Type of skewedwake correction model (switch) {1=uncoupled, 2=Pitt/Peters, 3=coupled} [used only when WakeMod=1]
True TipLoss  Use the Prandtl tiploss model? (flag) [used only when WakeMod=1]
True HubLoss  Use the Prandtl hubloss model? (flag) [used only when WakeMod=1]
True TanInd  Include tangential induction in BEMT calculations? (flag) [used only when WakeMod=1]
True AIDrag  Include the drag term in the axialinduction calculation? (flag) [used only when WakeMod=1]
True TIDrag  Include the drag term in the tangentialinduction calculation? (flag) [used only when WakeMod=1 and TanInd=TRUE]
"Default" IndToler  Convergence tolerance for BEMT nonlinear solve residual equation {or "default"} () [used only when WakeMod=1]
100 MaxIter  Maximum number of iteration steps () [used only when WakeMod=1]
====== BeddoesLeishman Unsteady Airfoil Aerodynamics Options ===================================== [used only when AFAeroMod=2]
3 UAMod  Unsteady Aero Model Switch (switch) {1=Baseline model (Original), 2=Gonzalez’s variant (changes in Cn,Cc,Cm), 3=Minemma/Pierce variant (changes in Cc and Cm)} [used only when AFAeroMod=2]
True FLookup  Flag to indicate whether a lookup for f' will be calculated (TRUE) or whether bestfit exponential equations will be used (FALSE); if FALSE S1S4 must be provided in airfoil input files (flag) [used only when AFAeroMod=2]
====== Airfoil Information =========================================================================
1 InCol_Alfa  The column in the airfoil tables that contains the angle of attack ()
2 InCol_Cl  The column in the airfoil tables that contains the lift coefficient ()
3 InCol_Cd  The column in the airfoil tables that contains the drag coefficient ()
4 InCol_Cm  The column in the airfoil tables that contains the pitchingmoment coefficient; use zero if there is no Cm column ()
0 InCol_Cpmin  The column in the airfoil tables that contains the Cpmin coefficient; use zero if there is no Cpmin column ()
8 NumAFfiles  Number of airfoil files used ()
"Airfoils/Cylinder1.dat" AFNames  Airfoil file names (NumAFfiles lines) (quoted strings)
"Airfoils/Cylinder2.dat"
"Airfoils/DU40_A17.dat"
"Airfoils/DU35_A17.dat"
"Airfoils/DU30_A17.dat"
"Airfoils/DU25_A17.dat"
"Airfoils/DU21_A17.dat"
"Airfoils/NACA64_A17.dat"
====== Rotor/Blade Properties =====================================================================
True UseBlCm  Include aerodynamic pitching moment in calculations? (flag)
"NRELOffshrBsline5MW_AeroDyn_blade.dat" ADBlFile(1)  Name of file containing distributed aerodynamic properties for Blade #1 ()
"NRELOffshrBsline5MW_AeroDyn_blade.dat" ADBlFile(2)  Name of file containing distributed aerodynamic properties for Blade #2 () [unused if NumBl < 2]
"NRELOffshrBsline5MW_AeroDyn_blade.dat" ADBlFile(3)  Name of file containing distributed aerodynamic properties for Blade #3 () [unused if NumBl < 3]
====== Tower Influence and Aerodynamics ============================================================= [used only when TwrPotent/=0, TwrShadow=True, or TwrAero=True]
12 NumTwrNds  Number of tower nodes used in the analysis () [used only when TwrPotent/=0, TwrShadow=True, or TwrAero=True]
TwrElev TwrDiam TwrCd
(m) (m) ()
0.0000000E+00 6.0000000E+00 1.0000000E+00
8.5261000E+00 5.7870000E+00 1.0000000E+00
1.7053000E+01 5.5740000E+00 1.0000000E+00
2.5579000E+01 5.3610000E+00 1.0000000E+00
3.4105000E+01 5.1480000E+00 1.0000000E+00
4.2633000E+01 4.9350000E+00 1.0000000E+00
5.1158000E+01 4.7220000E+00 1.0000000E+00
5.9685000E+01 4.5090000E+00 1.0000000E+00
6.8211000E+01 4.2960000E+00 1.0000000E+00
7.6738000E+01 4.0830000E+00 1.0000000E+00
8.5268000E+01 3.8700000E+00 1.0000000E+00
8.7600000E+01 3.8700000E+00 1.0000000E+00
====== Outputs ====================================================================================
True SumPrint  Generate a summary file listing input options and interpolated properties to "<rootname>.AD.sum"? (flag)
0 NBlOuts  Number of blade node outputs [0  9] ()
1, 9, 19 BlOutNd  Blade nodes whose values will be output ()
0 NTwOuts  Number of tower node outputs [0  9] ()
1, 2, 6 TwOutNd  Tower nodes whose values will be output ()
OutList  The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, ()
"RtAeroFxh"
"RtAeroFyh"
"RtAeroFzh"
"RtAeroMxh"
"RtAeroMyh"
"RtAeroMzh"
"RtAeroPwr"
END of input file (the word "END" must appear in the first 3 columns of this last OutList line)

Thank you for your help.
Best regards,
Riccardo.
 Attachments

 Wind.jpg (45.93 KiB) Viewed 2169 times

 Force.jpg (71.22 KiB) Viewed 2169 times

 Posts: 5738
 Joined: Thu Nov 03, 2005 4:38 pm
 Location: Boulder, CO
 Contact:
Re: Tower base loads due wind effect
Dear Riccardo,
I see an oscillation of about 30 cycles in 50 seconds, or 0.6 Hz. My guess is this is a 3P (3 per revolution) oscillation resulting from the 3bladed rotor operating in the sheared (from the 0.2 power law shear exponent) and skewed flow (from the 5deg shaft tilt) that you have enabled.
Best regards.
I see an oscillation of about 30 cycles in 50 seconds, or 0.6 Hz. My guess is this is a 3P (3 per revolution) oscillation resulting from the 3bladed rotor operating in the sheared (from the 0.2 power law shear exponent) and skewed flow (from the 5deg shaft tilt) that you have enabled.
Best regards.
Jason Jonkman, Ph.D.
Senior Engineer  National Wind Technology Center (NWTC)
National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway  Golden, CO 80401
+1 (303) 384 – 7026  Fax: +1 (303) 384 – 6901
nwtc.nrel.gov
Senior Engineer  National Wind Technology Center (NWTC)
National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway  Golden, CO 80401
+1 (303) 384 – 7026  Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

 Posts: 34
 Joined: Mon May 04, 2020 3:31 am
 Organization: Politecnico di Torino
 Location: Italia
Re: Tower base loads due wind effect
Dear Jason,
Thanks for your help, now the previsious ploblem is fixed.
Now I'm trying to extend the force analysis at notsteady state case. My model takes into account only the ucomponent of the wind, so there are differences between loads in the Z and Y directions due to the others two components of the wind developed by Turbsim (along y and z axis).
Can you suggest me any topic or document about how FAST V8 calculate these forces?
In other words, how can I find YawBrFyp and YawBrFzp from Wind1VelY and Wind1VelZ?
Best regards,
Riccardo.
Thanks for your help, now the previsious ploblem is fixed.
Now I'm trying to extend the force analysis at notsteady state case. My model takes into account only the ucomponent of the wind, so there are differences between loads in the Z and Y directions due to the others two components of the wind developed by Turbsim (along y and z axis).
Can you suggest me any topic or document about how FAST V8 calculate these forces?
In other words, how can I find YawBrFyp and YawBrFzp from Wind1VelY and Wind1VelZ?
Best regards,
Riccardo.

 Posts: 5738
 Joined: Thu Nov 03, 2005 4:38 pm
 Location: Boulder, CO
 Contact:
Re: Tower base loads due wind effect
Dear Riccardo,
Well, the transverse loads are impacted by the aerodynamic loads and structural response, including aeroelastic effects. I would suggest reviewing the FAST theory basis I referenced in the link in my post dated May 04, 2020 above.
Best regards
Well, the transverse loads are impacted by the aerodynamic loads and structural response, including aeroelastic effects. I would suggest reviewing the FAST theory basis I referenced in the link in my post dated May 04, 2020 above.
Best regards
Jason Jonkman, Ph.D.
Senior Engineer  National Wind Technology Center (NWTC)
National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway  Golden, CO 80401
+1 (303) 384 – 7026  Fax: +1 (303) 384 – 6901
nwtc.nrel.gov
Senior Engineer  National Wind Technology Center (NWTC)
National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway  Golden, CO 80401
+1 (303) 384 – 7026  Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

 Posts: 34
 Joined: Mon May 04, 2020 3:31 am
 Organization: Politecnico di Torino
 Location: Italia
Re: Tower base loads due wind effect
Dear Jason,
I am carrying out an Onshore test with test 24 with precon = 0, in particular I am finding it difficult to derive the wind values in the tangential and normal directions with respect to the reference system of the blade.
To do the test I am using the wind files obtained from TurbSim, from which in addition to the .bts file to be implemented in the FAST test input file, I also extract the spatial and temporal distribution of the u, v, w components of the wind that I use then to verify.
To evaluate the wind components on the blade node, I use azimuth to evaluate the position of the node and the time to derive the wind spectrum corresponding to that time step.
Furthermore, to take into account the 3 wind components in the blade reference system, I use the following equation:
[Vx_blade Vy_blade Vz_blade]^T = (R^T) *([u v w]^T)
where is it:
_R is the rotation matrix shown in Figure 1 with (rx ry rz) respectively (Azimuth Pitch Yaw);
Normal speed (V_norm) is equal to Vx_blade while tangential speed (V_tang) is equal to Vy_blade + RotSpeed * r.
Where r represents the radial position of the node.
Comparing the Vrel obtained as:
Vrel = sqrt (V_tang ^ 2 + V_norm ^ 2)
with the BαNβVrel output I do not find the same results.
Is there any error in my process?
I am carrying out an Onshore test with test 24 with precon = 0, in particular I am finding it difficult to derive the wind values in the tangential and normal directions with respect to the reference system of the blade.
To do the test I am using the wind files obtained from TurbSim, from which in addition to the .bts file to be implemented in the FAST test input file, I also extract the spatial and temporal distribution of the u, v, w components of the wind that I use then to verify.
To evaluate the wind components on the blade node, I use azimuth to evaluate the position of the node and the time to derive the wind spectrum corresponding to that time step.
Furthermore, to take into account the 3 wind components in the blade reference system, I use the following equation:
[Vx_blade Vy_blade Vz_blade]^T = (R^T) *([u v w]^T)
where is it:
_R is the rotation matrix shown in Figure 1 with (rx ry rz) respectively (Azimuth Pitch Yaw);
Normal speed (V_norm) is equal to Vx_blade while tangential speed (V_tang) is equal to Vy_blade + RotSpeed * r.
Where r represents the radial position of the node.
Comparing the Vrel obtained as:
Vrel = sqrt (V_tang ^ 2 + V_norm ^ 2)
with the BαNβVrel output I do not find the same results.
Is there any error in my process?
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Re: Tower base loads due wind effect
Dear Riccardo,
A few comments and questions:
Best regards,
A few comments and questions:
 Are pitch and yaw associated with the floating platform or wind turbine?
 Which structural DOFs are enabled in your model?
 Which rotation sequence are you assuming?
 The relative wind speed output from AeroDyn includes induction effects, which I don't see in your equation.
 I would expect the relative wind speed (not including induction) in global to be V_wind  v_struct, but you have a + sign; I'm not sure if this is related to the coordinate system you are using.
Best regards,
Jason Jonkman, Ph.D.
Senior Engineer  National Wind Technology Center (NWTC)
National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway  Golden, CO 80401
+1 (303) 384 – 7026  Fax: +1 (303) 384 – 6901
nwtc.nrel.gov
Senior Engineer  National Wind Technology Center (NWTC)
National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway  Golden, CO 80401
+1 (303) 384 – 7026  Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

 Posts: 34
 Joined: Mon May 04, 2020 3:31 am
 Organization: Politecnico di Torino
 Location: Italia
Re: Tower base loads due wind effect
Dear Jason,
I am verifying the BEM Theory implemented on my model, making comparisons with the FAST outputs.
I noticed some differences in the trends of pN and pT (normal and tangential load on the blade per unit of length), so I investigated more deeply, finding differences in the trends of a and a '(axial and tangential induction factor). From some tests I have found that the values of Cx and Cy obtained by me are the same as those obtained by FAST, imposing the same alpha and phi inputs. Therefore the error must be in one of the three corrections; since the skew correction only concerns the axial induction factor, and since the tangential induction factor is also wrong, I focused on the other two corrections and on the value of a '. In my model I used the formulas shown in the following document https://www.nrel.gov/docs/fy15osti/63217.pdf
In particular, I note that in the first 4 nodes the tangential induction factor leaving FAST is 0, while according to my calculations, being
TIF = (sigma * Cy) / (4 * F * sinPhi * cosPhi  sigma * Cy)
and since sigma and Cy different from 0, and F not infinite, I don't understand how it manages to be TIF = 0 in the first 4 nodes.
Here are the FAST outputs I used:
Cx = 'BαNβCx'
Cy = 'BαNβCy'
AIF = a = 'BαNβAxInd'
TIF = a '=' BαNβTnInd '
Phi = 'BαNβPhi'
Alpha = 'BαNβAlpha'
Thanks for your help, best regards.
Riccardo.
I am verifying the BEM Theory implemented on my model, making comparisons with the FAST outputs.
I noticed some differences in the trends of pN and pT (normal and tangential load on the blade per unit of length), so I investigated more deeply, finding differences in the trends of a and a '(axial and tangential induction factor). From some tests I have found that the values of Cx and Cy obtained by me are the same as those obtained by FAST, imposing the same alpha and phi inputs. Therefore the error must be in one of the three corrections; since the skew correction only concerns the axial induction factor, and since the tangential induction factor is also wrong, I focused on the other two corrections and on the value of a '. In my model I used the formulas shown in the following document https://www.nrel.gov/docs/fy15osti/63217.pdf
In particular, I note that in the first 4 nodes the tangential induction factor leaving FAST is 0, while according to my calculations, being
TIF = (sigma * Cy) / (4 * F * sinPhi * cosPhi  sigma * Cy)
and since sigma and Cy different from 0, and F not infinite, I don't understand how it manages to be TIF = 0 in the first 4 nodes.
Here are the FAST outputs I used:
Cx = 'BαNβCx'
Cy = 'BαNβCy'
AIF = a = 'BαNβAxInd'
TIF = a '=' BαNβTnInd '
Phi = 'BαNβPhi'
Alpha = 'BαNβAlpha'
Thanks for your help, best regards.
Riccardo.

 Posts: 5738
 Joined: Thu Nov 03, 2005 4:38 pm
 Location: Boulder, CO
 Contact:
Re: Tower base loads due wind effect
Dear Riccardo,
I'm not sure. There have been many changes to the BEM implementation in AeroDyn since the Ning et al paper you reference was published (to make the solution robust across all conditions, to make it compatible with the modularization framework, etc.). Unfortunately, I'm not ware of an updated reference that fully explains the current BEM algorithm. Your best bet is to review the AeroDyn source code to understand the algorithm. You may also want to run your model in debug mode to understand why your results differ.
Best regards,
I'm not sure. There have been many changes to the BEM implementation in AeroDyn since the Ning et al paper you reference was published (to make the solution robust across all conditions, to make it compatible with the modularization framework, etc.). Unfortunately, I'm not ware of an updated reference that fully explains the current BEM algorithm. Your best bet is to review the AeroDyn source code to understand the algorithm. You may also want to run your model in debug mode to understand why your results differ.
Best regards,
Jason Jonkman, Ph.D.
Senior Engineer  National Wind Technology Center (NWTC)
National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway  Golden, CO 80401
+1 (303) 384 – 7026  Fax: +1 (303) 384 – 6901
nwtc.nrel.gov
Senior Engineer  National Wind Technology Center (NWTC)
National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway  Golden, CO 80401
+1 (303) 384 – 7026  Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

 Posts: 34
 Joined: Mon May 04, 2020 3:31 am
 Organization: Politecnico di Torino
 Location: Italia
Re: Tower base loads due wind effect
Dear Jason,
I am trying to evaluate the difference in wind speed in the various nodes of the blade between my model and FAST without induction, for the moment I am concentrating on the x direction. To do this I am using an Onshore test with an average wind of 8.5 with turbulence obtained from Turbsim (.bts file). To derive the wind from FAST I am using the BαNβVUndx output, since the test is onshore the x in the blade reference system is the same as the global reference system which is the one used by turbsim.
While in my model I created a spatially (X, Y) and temporally discretized lookup table, using the '.u' file out of Turbsim, then in the lookup table I enter with Time (T), Yposition (Y ) and Zposition (Z), where in the case of an onshore test:
T = current timestep;
Y = sin (Azimuth) * r;
Z = cos (Azimuth) * r.
Where is it:
Azimuth = is the output of FAST
r = distance in the z direction between the node under consideration and the center of the hub in the blade reference system.
Furthermore, in the FF_interp function present in the source code of the inflow wind, I noticed that FAST obtains the 4 pairs of points (Y, Z) relating to 2 Time slices and then performs bilinear interpolation for each time slice. Linear interpolation is then used to interpolate between time slices.
For this reason I have imposed a linear interpolation in my LUT in the three dimensions.
Despite this there are differences between my model and FAST, in particular I noticed that as the nodes increase, a time lag is created (fig. 1). This does not happen in the case of a steady wind with power law exponent (fig. 2) where my model and FAST are practically identical.
Is it possible that there is a difference between the '.u' and '.bts' files coming out of Turbsim?
Is there something wrong with my approach?
Thanks a lot for the help, best regards.
Riccardo.
I am trying to evaluate the difference in wind speed in the various nodes of the blade between my model and FAST without induction, for the moment I am concentrating on the x direction. To do this I am using an Onshore test with an average wind of 8.5 with turbulence obtained from Turbsim (.bts file). To derive the wind from FAST I am using the BαNβVUndx output, since the test is onshore the x in the blade reference system is the same as the global reference system which is the one used by turbsim.
While in my model I created a spatially (X, Y) and temporally discretized lookup table, using the '.u' file out of Turbsim, then in the lookup table I enter with Time (T), Yposition (Y ) and Zposition (Z), where in the case of an onshore test:
T = current timestep;
Y = sin (Azimuth) * r;
Z = cos (Azimuth) * r.
Where is it:
Azimuth = is the output of FAST
r = distance in the z direction between the node under consideration and the center of the hub in the blade reference system.
Furthermore, in the FF_interp function present in the source code of the inflow wind, I noticed that FAST obtains the 4 pairs of points (Y, Z) relating to 2 Time slices and then performs bilinear interpolation for each time slice. Linear interpolation is then used to interpolate between time slices.
For this reason I have imposed a linear interpolation in my LUT in the three dimensions.
Despite this there are differences between my model and FAST, in particular I noticed that as the nodes increase, a time lag is created (fig. 1). This does not happen in the case of a steady wind with power law exponent (fig. 2) where my model and FAST are practically identical.
Is it possible that there is a difference between the '.u' and '.bts' files coming out of Turbsim?
Is there something wrong with my approach?
Thanks a lot for the help, best regards.
Riccardo.
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 Joined: Thu Nov 10, 2005 10:51 am
 Organization: Envision Energy USA
 Location: Colorado
 Location: Boulder, CO
 Contact:
Re: Tower base loads due wind effect
Riccardo,
A few comments:
1. Some older versions of FAST/InflowWind did interpolation differently than the current version. It now does a trilinear interpolation.
2. When InflowWind reads the FF grid files, it shifts them so that at time zero, the wind field starts half the grid width in front of the turbine. The initial X position is.
3. Keep in mind that X=0 at the undeflected tower centerline (not at the hub). Depending on where you've requested output from InflowWind, this could make a difference.
4. You will need to calculate an X position as well as Y, Z, and time. Are your blades rigid? Do you have tilt or precone in your model? These will make a difference as to where the blade nodes are, and thus what the wind velocity will be. In the current InflowWind, it is calculated this way:
A few comments:
1. Some older versions of FAST/InflowWind did interpolation differently than the current version. It now does a trilinear interpolation.
2. When InflowWind reads the FF grid files, it shifts them so that at time zero, the wind field starts half the grid width in front of the turbine. The initial X position is
Code: Select all
0.5*(NYGrids1)*dY
3. Keep in mind that X=0 at the undeflected tower centerline (not at the hub). Depending on where you've requested output from InflowWind, this could make a difference.
4. You will need to calculate an X position as well as Y, Z, and time. Are your blades rigid? Do you have tilt or precone in your model? These will make a difference as to where the blade nodes are, and thus what the wind velocity will be. In the current InflowWind, it is calculated this way:
Code: Select all
TimeShifted = t_requested + ( InitialXPosition  X )/MeanFFWindSpeed
Bonnie Jonkman
Envision Energy USA, 2016
National Renewable Energy Laboratory, 20032016
Envision Energy USA, 2016
National Renewable Energy Laboratory, 20032016

 Posts: 34
 Joined: Mon May 04, 2020 3:31 am
 Organization: Politecnico di Torino
 Location: Italia
Re: Tower base loads due wind effect
Dear Bonnie,
Thank you for your prompt reply. Regarding your comments:
1. The inflow wind source code that I have read, I believe it is that of the FAST executive that I am using, because it was present in the folder I downloaded when I installed FAST v8.16.
3. In the test that I used I set overhang=0, so I think that the Hub is at the same x coordinate respect undeflected center line.
4. In this case I don't calculate the x position because is an onshore test, but in the other cases I calculate this position in my model to evaluate the time shifted (with the same equation you suggest). Moreover, my blades and tower are rigid and I set Tilt=0 and precone=0.
Regarding point 2, I have not set any shift in the x position. Do you think this can solve my problem? Could there be more?
Thank you again for your help, best regards.
Riccardo.
Thank you for your prompt reply. Regarding your comments:
1. The inflow wind source code that I have read, I believe it is that of the FAST executive that I am using, because it was present in the folder I downloaded when I installed FAST v8.16.
3. In the test that I used I set overhang=0, so I think that the Hub is at the same x coordinate respect undeflected center line.
4. In this case I don't calculate the x position because is an onshore test, but in the other cases I calculate this position in my model to evaluate the time shifted (with the same equation you suggest). Moreover, my blades and tower are rigid and I set Tilt=0 and precone=0.
Regarding point 2, I have not set any shift in the x position. Do you think this can solve my problem? Could there be more?
Thank you again for your help, best regards.
Riccardo.

 Posts: 575
 Joined: Thu Nov 10, 2005 10:51 am
 Organization: Envision Energy USA
 Location: Colorado
 Location: Boulder, CO
 Contact:
Re: Tower base loads due wind effect
I don't know how you have defined your nodes, but if you are matching at the hub node and NOT matching as you move out radially from the hub, I would suspect that there is an error in one or more of the position calculations.
Perhaps you can calculate the equivalent shift on your plot by matching the peaks and backcalculating how far it is off. Or just step through it using a debugger to identify differences.
Perhaps you can calculate the equivalent shift on your plot by matching the peaks and backcalculating how far it is off. Or just step through it using a debugger to identify differences.
Bonnie Jonkman
Envision Energy USA, 2016
National Renewable Energy Laboratory, 20032016
Envision Energy USA, 2016
National Renewable Energy Laboratory, 20032016

 Posts: 34
 Joined: Mon May 04, 2020 3:31 am
 Organization: Politecnico di Torino
 Location: Italia
Re: Tower base loads due wind effect
Dear Bonnie,
With the imposition of an initial x value, the differences between the two graphs have decreased, but they are still present.
So to evaluate if, as you suggested, there is some error in evaluating the position of the nodes, I used 'Wind1VelX' as the output of FAST, so that it was a fixed point and that it was therefore comparable with what I get from Turbsim. To make the comparison, therefore, I set the coordinates of a node of the wind grid in the Inflowind input file. In this way I bypassed the node coordinates problem and therefore I expected an equal trend with only a time offset, due to the initial x value imposed in the Inflowind routine.
However, as you can see from figures 1 and 2, the analogous trend that I expected is obtained only for the hub coordinates (fig1), while if I move to the coordinates of another point of the grid (fig2), the differences do not they only limit more to the time offset.
Here is the Turbsim input file that I am using for the test:
With the imposition of an initial x value, the differences between the two graphs have decreased, but they are still present.
So to evaluate if, as you suggested, there is some error in evaluating the position of the nodes, I used 'Wind1VelX' as the output of FAST, so that it was a fixed point and that it was therefore comparable with what I get from Turbsim. To make the comparison, therefore, I set the coordinates of a node of the wind grid in the Inflowind input file. In this way I bypassed the node coordinates problem and therefore I expected an equal trend with only a time offset, due to the initial x value imposed in the Inflowind routine.
However, as you can see from figures 1 and 2, the analogous trend that I expected is obtained only for the hub coordinates (fig1), while if I move to the coordinates of another point of the grid (fig2), the differences do not they only limit more to the time offset.
Here is the Turbsim input file that I am using for the test:
Code: Select all
TurbSim Input File. Valid for TurbSim v1.06.00, 21Sep2012
Runtime Options
1393911158 RandSeed1  First random seed (2147483648 to 2147483647)
RANLUX RandSeed2  Second random seed (2147483648 to 2147483647) for intrinsic pRNG, or an alternative pRNG: "RanLux" or "RNSNLW"
False WrBHHTP  Output hubheight turbulence parameters in binary form? (Generates RootName.bin)
False WrFHHTP  Output hubheight turbulence parameters in formatted form? (Generates RootName.dat)
False WrADHH  Output hubheight timeseries data in AeroDyn form? (Generates RootName.hh)
True WrADFF  Output fullfield timeseries data in TurbSim/AeroDyn form? (Generates Rootname.bts)
False WrBLFF  Output fullfield timeseries data in BLADED/AeroDyn form? (Generates RootName.wnd)
False WrADTWR  Output tower timeseries data? (Generates RootName.twr)
True WrFMTFF  Output fullfield timeseries data in formatted (readable) form? (Generates RootName.u, RootName.v, RootName.w)
False WrACT  Output coherent turbulence time steps in AeroDyn form? (Generates RootName.cts)
True Clockwise  Clockwise rotation looking downwind? (used only for fullfield binary files  not necessary for AeroDyn)
0 ScaleIEC  Scale IEC turbulence models to exact target standard deviation? [0=no additional scaling; 1=use hub scale uniformly; 2=use individual scales]
Turbine/Model Specifications
13 NumGrid_Z  Vertical gridpoint matrix dimension
13 NumGrid_Y  Horizontal gridpoint matrix dimension
0.05 TimeStep  Time step [seconds]
1200 AnalysisTime  Length of analysis time series [seconds] (program will add time if necessary: AnalysisTime = MAX(AnalysisTime, UsableTime+GridWidth/MeanHHWS) )
1200 UsableTime  Usable length of output time series [seconds] (program will add GridWidth/MeanHHWS seconds)
90 HubHt  Hub height [m] (should be > 0.5*GridHeight)
145.00 GridHeight  Grid height [m]
145.00 GridWidth  Grid width [m] (should be >= 2*(RotorRadius+ShaftLength))
0 VFlowAng  Vertical mean flow (uptilt) angle [degrees]
0 HFlowAng  Horizontal mean flow (skew) angle [degrees]
Meteorological Boundary Conditions
"IECKAI" TurbModel  Turbulence model ("IECKAI"=Kaimal, "IECVKM"=von Karman, "GP_LLJ", "NWTCUP", "SMOOTH", "WF_UPW", "WF_07D", "WF_14D", "TIDAL", or "NONE")
"3" IECstandard  Number of IEC 61400x standard (x=1,2, or 3 with optional 614001 edition number (i.e. "1Ed2") )
"B" 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 1year wind, "xEWM50"=extreme 50year wind, where x=wind turbine class 1, 2, or 3)
default ETMc  IEC Extreme Turbulence Model "c" parameter [m/s]
"PL" WindProfileType  Wind profile type ("JET";"LOG"=logarithmic;"PL"=power law;"H2L"=Log law for TIDAL spectral model;"IEC"=PL on rotor disk, LOG elsewhere; or "default")
90 RefHt  Height of the reference wind speed [m]
8.5 URef  Mean (total) wind speed at the reference height [m/s] (or "default" for JET wind profile)
default ZJetMax  Jet height [m] (used only for JET wind profile, valid 70490 m)
0.14 PLExp  Power law exponent [] (or "default")
0.03 Z0  Surface roughness length [m] (or "default")
NonIEC Meteorological Boundary Conditions
default Latitude  Site latitude [degrees] (or "default")
0.05 RICH_NO  Gradient Richardson number
default UStar  Friction or shear velocity [m/s] (or "default")
default ZI  Mixing layer depth [m] (or "default")
default PC_UW  Hub mean u'w' Reynolds stress (or "default")
default PC_UV  Hub mean u'v' Reynolds stress (or "default")
default PC_VW  Hub mean v'w' Reynolds stress (or "default")
default IncDec1  ucomponent coherence parameters (e.g. "10.0 0.3e3" in quotes) (or "default")
default IncDec2  vcomponent coherence parameters (e.g. "10.0 0.3e3" in quotes) (or "default")
default IncDec3  wcomponent coherence parameters (e.g. "10.0 0.3e3" in quotes) (or "default")
default CohExp  Coherence exponent (or "default")
Coherent Turbulence Scaling Parameters
"C:\Users\Luigi\Dropbox\Tesi\NREL\Turbsim\coh_events\EventData\" CTEventPath  Name of the path where event data files are located
"Random" CTEventFile  Type of event files ("LES", "DNS", or "RANDOM")
true Randomize  Randomize the disturbance scale and locations? (true/false)
1.0 DistScl  Disturbance scale (ratio of wave height to rotor disk). (Ignored when Randomize = true.)
0.5 CTLy  Fractional location of tower centerline from right (looking downwind) to left side of the dataset. (Ignored when Randomize = true.)
0.5 CTLz  Fractional location of hub height from the bottom of the dataset. (Ignored when Randomize = true.)
30.0 CTStartTime  Minimum start time for coherent structures in RootName.cts [seconds]
==================================================
NOTE: Do not add or remove any lines in this file!
==================================================
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