Dear Dr. Jonkman,
Thanks for your swift reply. So, your meaning by the primary input file is the test file. Actually, it set to 1 before as it was! You can see Test 24 in the following:
Thanks,
Best regards,
Sina
Dear Sina,
So, your not using BeamDyn.
Is your controller inducing oscillations? I would disable ServoDyn by setting CompServo=0.
You’ve verified that the tilt and yaw are zero? (ShftTilt=0, NacYaw=0 in ElastoDyn).
Best regards,
Dear Dr. Jonkman,
Thanks for your reply. It is open loop, meaning there is no controller. I just want to see how much my model is closely behave as the FAST. Yes, ShftTilt=0, NacYaw=0 in ElastoDyn. Should I set CompServo=0?
Thanks,
Best regards,
Sina
Dear Sina.
Yes, set CompServo=0. I’m trying to help you eliminate all features that could result in transient dynamics.
Best regards,
Dear Dr. Jonkman,
Thanks again for your prompt reply. I appreciate it. I set that flag to zero but there is still oscillation. For instance, this is the signal of RtTSR:
Thanks
Best regards,
Sina
Dear Sina,
Well, I’m sure there is something set incorrectly in one of the FAST input files. I would plot the structural responses from ElastoDyn to see if there is anything time-varying (rotor speed, pitch angle, yaw angle, blade deflection, tower deflection, platform displacement – I would expect all of these to be constant or zero).
Best regards,
Dear Dr. Jonkman,
Thank you so much. I really appreciate it. Let me know when you got the correct results. Meanwhile, I am double-checking all the settings to see whether something sets incorrectly.
Thanks
Best regards,
Sina
Dear Dr. Jonkman,
I double-checked all of the comments you sent to me. It seems I followed whatever you advised me. Because there is only three files to be changed, I am putting them here, in case something does not set correctly:
NRELOffshrBsline5MW_InflowWind_12mps:
------- 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 .ech (flag)
2 WindType - switch for wind file type (1=steady; 2=uniform; 3=binary TurbSim FF; 4=binary Bladed-style 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] =========================
0 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] ============================
“Step-Wind.wnd” 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 Full-Field files [used only for WindType = 3] ==============
“TurbSim_Hydro.bts” Filename - Name of the Full field wind file to use (.bts)
================== Parameters for Binary Bladed-style Full-Field files [used only for WindType = 4] =========
“Turbsim_Hydro.twr” FilenameRoot - Rootname of the full-field wind file to use (.wnd, .sum)
True TowerFile - Have tower file (.twr) (flag)
================== Parameters for HAWC-format binary files [Only used with WindType = 5] =====================
“wasp\Output\basic_5u.bin” FileName_u - name of the file containing the u-component fluctuating wind (.bin)
“wasp\Output\basic_5v.bin” FileName_v - name of the file containing the v-component fluctuating wind (.bin)
“wasp\Output\basic_5w.bin” FileName_w - name of the file containing the w-component 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 HAWC-format files) ---------------------------------
5 URef - Mean u-component wind speed at the reference height (m/s)
2 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 .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” X-direction wind velocity at point WindList(1)
“Wind1VelY” Y-direction wind velocity at point WindList(1)
“Wind1VelZ” Z-direction 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)
------- 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 Pre-Design (10046_009.pdf) and REpower 5M 5MW (5m_uk.pdf)
---------------------- SIMULATION CONTROL --------------------------------------
False Echo - Echo input data to “.ech” (flag)
3 Method - Integration method: {1: RK4, 2: AB4, or 3: ABM4} (-)
“default” DT - Integration time step (s)
---------------------- ENVIRONMENTAL CONDITION ---------------------------------
0 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 - Rotor-teeter DOF (flag) [unused for 3 blades]
False DrTrDOF - Drivetrain rotational-flexibility DOF (flag)
False GenDOF - Generator DOF (flag)
False YawDOF - Yaw DOF (flag)
False TwFADOF1 - First fore-aft tower bending-mode DOF (flag)
False TwFADOF2 - Second fore-aft tower bending-mode DOF (flag)
False TwSSDOF1 - First side-to-side tower bending-mode DOF (flag)
False TwSSDOF2 - Second side-to-side tower bending-mode 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 out-of-plane blade-tip displacement (meters)
0 IPDefl - Initial in-plane blade-tip deflection (meters)
19.94 BlPitch(1) - Blade 1 initial pitch (degrees)
19.94 BlPitch(2) - Blade 2 initial pitch (degrees)
19.94 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)
11 RotSpeed - Initial or fixed rotor speed (rpm)
0 NacYaw - Initial or fixed nacelle-yaw angle (degrees)
0 TTDspFA - Initial fore-aft tower-top displacement (meters)
0 TTDspSS - Initial side-to-side tower-top 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)
-2.5 PreCone(1) - Blade 1 cone angle (degrees)
-2.5 PreCone(2) - Blade 2 cone angle (degrees)
-2.5 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 - Delta-3 angle for teetering rotors (degrees) [unused for 3 blades]
0 AzimB1Up - Azimuth value to use for I/O when blade 1 points up (degrees)
-5.0191 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 tower-top to the nacelle CM (meters)
0 NacCMyn - Lateral distance from the tower-top to the nacelle CM (meters)
1.75 NacCMzn - Vertical distance from the tower-top to the nacelle CM (meters)
-3.09528 NcIMUxn - Downwind distance from the tower-top to the nacelle IMU (meters)
0 NcIMUyn - Lateral distance from the tower-top to the nacelle IMU (meters)
2.23336 NcIMUzn - Vertical distance from the tower-top to the nacelle IMU (meters)
1.96256 Twr2Shft - Vertical distance from the tower-top to the rotor shaft (meters)
87.6 TowerHt - Height of tower above ground level [onshore] or MSL [offshore] (meters)
10 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)
-89.9155 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) - Tip-brake mass, blade 1 (kg)
0 TipMass(2) - Tip-brake mass, blade 2 (kg)
0 TipMass(3) - Tip-brake 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)
7.46633E+06 PtfmMass - Platform mass (kg)
4.22923E+09 PtfmRIner - Platform inertia for roll tilt rotation about the platform CM (kg m^2)
4.22923E+09 PtfmPIner - Platform inertia for pitch tilt rotation about the platform CM (kg m^2)
1.6423E+08 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]
---------------------- ROTOR-TEETER --------------------------------------------
0 TeetMod - Rotor-teeter spring/damper model {0: none, 1: standard, 2: user-defined from routine UserTeet} (switch) [unused for 3 blades]
0 TeetDmpP - Rotor-teeter damper position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetDmp - Rotor-teeter damping constant (N-m/(rad/s)) [used only for 2 blades and when TeetMod=1]
0 TeetCDmp - Rotor-teeter rate-independent Coulomb-damping moment (N-m) [used only for 2 blades and when TeetMod=1]
0 TeetSStP - Rotor-teeter soft-stop position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetHStP - Rotor-teeter hard-stop position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetSSSp - Rotor-teeter soft-stop linear-spring constant (N-m/rad) [used only for 2 blades and when TeetMod=1]
0 TeetHSSp - Rotor-teeter hard-stop linear-spring constant (N-m/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 (N-m/rad)
6.215E+06 DTTorDmp - Drivetrain torsional damper (N-m/(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_OC3Hywind_ElastoDyn_Tower.dat” TwrFile - Name of file containing tower properties (quoted string)
---------------------- OUTPUT --------------------------------------------------
True SumPrint - Print summary data to “.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)
30 TStart - Time to begin tabular output (s) (currently unused)
1 DecFact - Decimation factor for tabular output {1: output every time step} (-) (currently unused)
1 NTwGages - Number of tower nodes that have strain gages for output [0 to 9] (-)
10 TwrGagNd - List of tower nodes that have strain gages [1 to TwrNodes] (-) [unused if NTwGages=0]
1 NBlGages - Number of blade nodes that have strain gages for output [0 to 9] (-)
9 BldGagNd - List of blade nodes that have strain gages [1 to BldNodes] (-) [unused if NBlGages=0]
------- FAST v8.16.* INPUT FILE ------------------------------------------------
FAST Certification Test #24: NREL 5.0 MW Baseline Wind Turbine with OC3 Hywind Configuration, for use in offshore analysis
---------------------- SIMULATION CONTROL --------------------------------------
False Echo - Echo input data to .ech (flag)
“FATAL” AbortLevel - Error level when simulation should abort (string) {“WARNING”, “SEVERE”, “FATAL”}
60 TMax - Total run time (s)
0.0125 DT - Recommended module time step (s)
1 InterpOrder - Interpolation order for input/output time history (-) {1=linear, 2=quadratic}
0 NumCrctn - Number of correction iterations (-) {0=explicit calculation, i.e., no corrections}
1.5 DT_UJac - Time between calls to get Jacobians (s)
1E+06 UJacSclFact - Scaling factor used in Jacobians (-)
---------------------- FEATURE SWITCHES AND FLAGS ------------------------------
1 CompElast - Compute structural dynamics (switch) {1=ElastoDyn; 2=ElastoDyn + BeamDyn for blades}
1 CompInflow - Compute inflow wind velocities (switch) {0=still air; 1=InflowWind; 2=external from OpenFOAM}
2 CompAero - Compute aerodynamic loads (switch) {0=None; 1=AeroDyn v14; 2=AeroDyn v15}
0 CompServo - Compute control and electrical-drive dynamics (switch) {0=None; 1=ServoDyn}
0 CompHydro - Compute hydrodynamic loads (switch) {0=None; 1=HydroDyn}
0 CompSub - Compute sub-structural dynamics (switch) {0=None; 1=SubDyn}
0 CompMooring - Compute mooring system (switch) {0=None; 1=MAP++; 2=FEAMooring; 3=MoorDyn; 4=OrcaFlex}
0 CompIce - Compute ice loads (switch) {0=None; 1=IceFloe; 2=IceDyn}
---------------------- INPUT FILES ---------------------------------------------
“5MW_Baseline/NRELOffshrBsline5MW_OC3Hywind_ElastoDyn.dat” EDFile - Name of file containing ElastoDyn input parameters (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_BeamDyn.dat” BDBldFile(1) - Name of file containing BeamDyn input parameters for blade 1 (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_BeamDyn.dat” BDBldFile(2) - Name of file containing BeamDyn input parameters for blade 2 (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_BeamDyn.dat” BDBldFile(3) - Name of file containing BeamDyn input parameters for blade 3 (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_InflowWind_12mps.dat” InflowFile - Name of file containing inflow wind input parameters (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_OC3Hywind_AeroDyn15.dat” AeroFile - Name of file containing aerodynamic input parameters (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_OC3Hywind_ServoDyn.dat” ServoFile - Name of file containing control and electrical-drive input parameters (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_OC3Hywind_HydroDyn.dat” HydroFile - Name of file containing hydrodynamic input parameters (quoted string)
“unused” SubFile - Name of file containing sub-structural input parameters (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_OC3Hywind_MAP.dat” MooringFile - Name of file containing mooring system input parameters (quoted string)
“unused” IceFile - Name of file containing ice input parameters (quoted string)
---------------------- OUTPUT --------------------------------------------------
True SumPrint - Print summary data to “.sum” (flag)
1 SttsTime - Amount of time between screen status messages (s)
99999 ChkptTime - Amount of time between creating checkpoint files for potential restart (s)
0.0125 DT_Out - Time step for tabular output (s) (or “default”)
0 TStart - Time to begin tabular output (s)
2 OutFileFmt - Format for tabular (time-marching) output file (switch) {1: text file [.out], 2: binary file [.outb], 3: both}
True TabDelim - Use tab delimiters in text tabular output file? (flag) {uses spaces if false}
“ES10.3E2” OutFmt - Format used for text tabular output, excluding the time channel. Resulting field should be 10 characters. (quoted string)
---------------------- LINEARIZATION -------------------------------------------
False Linearize - Linearization analysis (flag)
2 NLinTimes - Number of times to linearize (-) [>=1] [unused if Linearize=False]
30, 60 LinTimes - List of times at which to linearize (s) [1 to NLinTimes] [unused if Linearize=False]
1 LinInputs - Inputs included in linearization (switch) {0=none; 1=standard; 2=all module inputs (debug)} [unused if Linearize=False]
1 LinOutputs - Outputs included in linearization (switch) {0=none; 1=from OutList(s); 2=all module outputs (debug)} [unused if Linearize=False]
False LinOutJac - Include full Jacobians in linearization output (for debug) (flag) [unused if Linearize=False; used only if LinInputs=LinOutputs=2]
False LinOutMod - Write module-level linearization output files in addition to output for full system? (flag) [unused if Linearize=False]
---------------------- VISUALIZATION ------------------------------------------
0 WrVTK - VTK visualization data output: (switch) {0=none; 1=initialization data only; 2=animation}
2 VTK_type - Type of VTK visualization data: (switch) {1=surfaces; 2=basic meshes (lines/points); 3=all meshes (debug)} [unused if WrVTK=0]
false VTK_fields - Write mesh fields to VTK data files? (flag) {true/false} [unused if WrVTK=0]
15 VTK_fps - Frame rate for VTK output (frames per second){will use closest integer multiple of DT} [used only if WrVTK=2]
Thanks,
Best regards,
Sina
Dear Sina,
You’ve disabled all structural DOFs and eliminated shaft tilt, yaw, wind direction, and wind shear. Do you have tower influence or tower shadow enabled in AeroDyn v15? These could also induce skewed flow.
Best regards,
Dear Dr. Jonkman,
Thanks for your reply. This my file that is NRELOffshrBsline5MW_OC3Hywind_AeroDyn15:
------- AERODYN v15.03.* INPUT FILE ------------------------------------------------
NREL 5.0 MW offshore baseline aerodynamic input properties.
====== General Options ============================================================================
False Echo - Echo the input to “.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}
2 AFAeroMod - Type of blade airfoil aerodynamics model (switch) {1=steady model, 2=Beddoes-Leishman unsteady model}
1 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)
True TwrAero - Calculate tower aerodynamic loads? (flag)
False FrozenWake - Assume frozen wake during linearization? (flag) [used only when WakeMod=1 and when linearizing]
====== Environmental Conditions ===================================================================
1.225 AirDens - Air density (kg/m^3)
1.464E-05 KinVisc - Kinematic air viscosity (m^2/s)
335 SpdSound - Speed of sound (m/s)
====== Blade-Element/Momentum Theory Options ====================================================== [used only when WakeMod=1]
2 SkewMod - Type of skewed-wake correction model (switch) {1=uncoupled, 2=Pitt/Peters, 3=coupled} [used only when WakeMod=1]
True TipLoss - Use the Prandtl tip-loss model? (flag) [used only when WakeMod=1]
True HubLoss - Use the Prandtl hub-loss model? (flag) [used only when WakeMod=1]
true TanInd - Include tangential induction in BEMT calculations? (flag) [used only when WakeMod=1]
False AIDrag - Include the drag term in the axial-induction calculation? (flag) [used only when WakeMod=1]
False TIDrag - Include the drag term in the tangential-induction 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]
====== Beddoes-Leishman 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 best-fit exponential equations will be used (FALSE); if FALSE S1-S4 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 pitching-moment 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]
11 NumTwrNds - Number of tower nodes used in the analysis (-) [used only when TwrPotent/=0, TwrShadow=True, or TwrAero=True]
TwrElev TwrDiam TwrCd
(m) (m) (-)
1.0000000E+01 6.5000000E+00 1.0000000E+00
1.7760000E+01 6.2400000E+00 1.0000000E+00
2.5520000E+01 5.9700000E+00 1.0000000E+00
3.3280000E+01 5.7100000E+00 1.0000000E+00
4.1040000E+01 5.4500000E+00 1.0000000E+00
4.8800000E+01 5.1800000E+00 1.0000000E+00
5.6560000E+01 4.9200000E+00 1.0000000E+00
6.4320000E+01 4.6600000E+00 1.0000000E+00
7.2080000E+01 4.4000000E+00 1.0000000E+00
7.9840000E+01 4.1300000E+00 1.0000000E+00
8.7600000E+01 3.8700000E+00 1.0000000E+00
====== Outputs ===========================================================================
Thanks,
Best regards,
Sina
Dear Sina,
I see that you’ve enabled tower potential flow (TwrPotent=1). You should get constant results after disabling this feature (TwrPotent=0).
Best regards,
Dear Dr. Jonkman,
Thank you so much. Now, I can get a fixed and clean signal. But there is a big problem! When I apply different inputs (pitch angles) and different step wind inflows, I get the same rotor speed that is always equal to the initial condition! It seems that it plays as a gain of one that directly send out its input (rotor speed as its initial condition) directly to the output. It seems that the control signal (pitch angel) and the wind speed do not any affect on the rotor speed!
In addition, when I apply the input of 10.45 deg and the wind speed of 15 m/s I get this power coefficient:
, which is very weird because it should not be negative!
I have another question. When I create my own folder, I get this error:
Error reported by S-function ‘FAST_SFunc’ in ‘OpenLoop_ModelVerfication/FAST
Nonlinear Wind Turbine/S-Function’:
FAST_InitializeAll:FAST_Init:FAST_ReadPrimaryFile:OpenFInpFile:The input file,
“…..\CertTest\Test24.fst”, was not found.
I can only run Simulink files located exactly in the “Samples” folder. It seems that there might be some files located in this folder that needed to be located to other folders of mine. However, I have already added the “ReadFASTbinary”, but still gets the same error.
Thanks
Best regards,
Sina
Dear Sina,
When you disable the generator DOF, the generator will rotate at a fixed speed (the initial speed) regardless of the torques applied. If you want time-varying generator speed, you must enable the generator DOF in ElastoDyn (GenDOF = True).
The error you are getting is not related to the location of ReadFASTBinary.m, but is related to the location of your FAST primary input file relative to the location of the FAST-SFunction. If the path and filename “…..\CertTest\Test24.fst” is incorrect, fix it.
Best regards,
Dear Dr. Jonkman,
Thanks for your prompt response. I return the DOF of the generator. But there is a problem. When I apply equilibrium points for the pitch and wind speed and with the initial condition in rotor speed at its rated value, then I expect that it stays in its rated value for the rotor speed, but it increases the rotor speed and track the value above the rated value making the CP (power coefficient) is zero. It seems strange because a nonlinear plant at its equilibrium points along with its initial conditions should stay near it.
Thanks,
Best regards,
Sina
Dear Sina,
It sounds like you’ve enabled the generator DOF, but haven’t activated any generator torque within ServoDyn, thus, the rotor is accelerating until the aerodynamic power drops to zero.
Best regards,
Dear Dr. Jonkman,
Thanks for your fast response. Yes, it makes sense. I corrected it. But there is a problem. Actually, the rotor speed does not stay at its initial value when I apply equilibrium points in it. It has a little steady-steady state error. It finally goes to 1.24 rad/s instead of the rated value that is 1.267 rad/s! When I apply different operating points, I get a different rotor speed. For instance, for the if the wind speed is 22m/s and pitch angle is 19.94 deg, the rotor speed goes from 1.267 to 1.24. And when I apply a wind speed of 15m/s and the pitch angle of 10.45 deg, it goes to 1.18! What is the underlying cause of this problem?
Thanks,
Best regards,
Sina
Dear Sina,
I gather based on your description that the aerodynamic torque and generator torque are not balanced for the given wind speed, blade-pitch angle, and generator torque, so, the rotor speed will accelerate/decelerate until they are balanced.
Best regards,
Dear Dr. Jonkman,
Thanks for responding me with celerity. So, how can I balance them? Do you mean because I deactivated structural degree of freedom it is unbalanced? Do you mean now the equilibrium points has changed due to changes of the dynamics?
Thanks,
Best regards,
Sina
Dear Sina,
Yes, you’ve disabled the structural DOFs and eliminated shaft tilt, so, the aerodynamic loads differ, and the blade-pitch angles appropriate to each mean wind speed will change. You’ll have to calculate the blade-pitch angle at each wind speed necessary to obtain the desired rotor speed, given the desired torque. Or simply enable the blade-pitch controller and it will do that for you.
Best regards,
Dear Dr. Jonkman,
Thank you so much. I got it.
Best regards,
Sina