Thanks @Jason.Jonkman. I will take this first approach.
Regards,
AOAW
Hi @Jason.Jonkman I have set GenDOF = false and RotSpeed = 0 and I received the following error:
FAST_Solution:FAST_AdvanceStates:ED_ABM4:ED_CalcContStateDeriv:SetCoordSy:Small angle assumption
violated in SUBROUTINE SmllRotTrans() due to a large blade deflection (ElastoDyn SetCoordSy). The
solution may be inaccurate. Simulation continuing, but future warnings from SmllRotTrans() will
be suppressed. Additional debugging message from SUBROUTINE SmllRotTrans(): 0.75 s
FAST_Solution:FAST_AdvanceStates:SolveOption2c_Inp2AD_SrvD:InflowWind_CalcOutput:CalcOutput:IfW_FF
Wind_CalcOutput [position=(-230.26, -245.8, 117.55) in wind-file coordinates]: FF wind array
boundaries violated: Grid too small in Y direction. Y=-245.8; Y boundaries = [-200, 200]
OpenFAST encountered an error at simulation time 1 of 3600 seconds. Simulation error level: FATAL ERROR
By way of reminder, I am parking turbine in extreme wind so wind speed is 45 m/s. Let me know how I could solve this problem.
Thank you.
Regards,
AOAW
Hi @Jason.Jonkman just checking if you were able to figure out what might be the cause of this error. I am still trying to decipher but no luck as yet.
Regards,
AOAW
Dear @Andre.White,
It sounds like your model has gone unstable. Can you clarify your simulation settings? It sounds like youâve parked the rotor with GenDOF = False and RotSpeed = 0.0 rpm and have set the pitch angles to BlPitch = 91.5deg. Can you confirm? Are you getting these errors only for certain yaw misalignments (wind directions)?
Best regards,
Hi @Jason.Jonkman I have responded to this on another forum I have created as it deals with modelling a parked turbine and think it is more appropriate to shift the discussion there.
Regards,
AOAW
Dear @Jason.Jonkman ,
I am doing simulations of monopile-supported offshore wind turbines using OPENFAST (including soildyn module) downloaded from GitHub. Only DISCON and OPENFAST source code have been recompiled, and all input files have not been modified. Three foundation models including fixed bottom model, REDWIN model and CS model in OC6 phaseII have been used for simulations. However, the simulations with fixed bottom model and REDWIN model aborted with a few errors, and relevant information was attached below. And can you provide another available OPENFAST resource code and r-test file?
Thanks in advance.
Best regards,
Fixed bottom model
REDWIN model
CS model in OC6 phaseII
Dear @Kevin.Chang,
The issue with your fixed-bottom set-up sounds like a numerical instability. Have you set solver settings typical for fixed offshore wind turbines with SubDyn enabled, e.g., DT sufficiently small to solve the natural frequencies and excitation frequencies of your model, NumCrctn = 1, and UJacSclFact equal to a value roughly the same order of magnitude as the total system mass in kg?
The issue with your REDWIN set-up is that the DLL cannot be loaded. Does DLL_FileName in your SoilDyn input file refer to the correct name and location of the DLL?
Iâm not sure I understand your last question, but the OC6 Phase II model is likely the best example model with SoilDyn available so far.
Best regards,
Dear @Jason.Jonkman ,
(1) After setting NumCrctn=1, the same error presented above still occurs. Here is my input files.
------- OpenFAST EXAMPLE INPUT FILE -------------------------------------------
FAST Certification Test #19: NREL 5.0 MW Baseline Wind Turbine with OC3 Monopile RF Configuration, for use in offshore analysis
---------------------- SIMULATION CONTROL --------------------------------------
True Echo - Echo input data to <RootName>.ech (flag)
"FATAL" AbortLevel - Error level when simulation should abort (string) {"WARNING", "SEVERE", "FATAL"}
60 TMax - Total run time (s)
0.0001 DT - Recommended module time step (s)
2 InterpOrder - Interpolation order for input/output time history (-) {1=linear, 2=quadratic}
1 NumCrctn - Number of correction iterations (-) {0=explicit calculation, i.e., no corrections}
99999 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}
1 CompServo - Compute control and electrical-drive dynamics (switch) {0=None; 1=ServoDyn}
1 CompHydro - Compute hydrodynamic loads (switch) {0=None; 1=HydroDyn}
1 CompSub - Compute sub-structural dynamics (switch) {0=None; 1=SubDyn; 2=External Platform MCKF}
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}
0 CompSoil - Compute soil-structural dynamics (switch) {0=None; 1=with SubDyn mesh}
0 MHK - MHK turbine type (switch) {0=Not an MHK turbine; 1=Fixed MHK turbine; 2=Floating MHK turbine}
---------------------- ENVIRONMENTAL CONDITIONS --------------------------------
9.80665 Gravity - Gravitational acceleration (m/s^2)
1.225 AirDens - Air density (kg/m^3)
1027 WtrDens - Water density (kg/m^3)
1.464E-05 KinVisc - Kinematic viscosity of working fluid (m^2/s)
335 SpdSound - Speed of sound in working fluid (m/s)
103500 Patm - Atmospheric pressure (Pa) [used only for an MHK turbine cavitation check]
1700 Pvap - Vapour pressure of working fluid (Pa) [used only for an MHK turbine cavitation check]
20 WtrDpth - Water depth (m)
0 MSL2SWL - Offset between still-water level and mean sea level (m) [positive upward]
---------------------- INPUT FILES ---------------------------------------------
"NRELOffshrBsline5MW_OC3Monopile_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)
"NRELOffshrBsline5MW_OC3Monopile_AeroDyn15.dat" AeroFile - Name of file containing aerodynamic input parameters (quoted string)
"NRELOffshrBsline5MW_OC3Monopile_ServoDyn.dat" ServoFile - Name of file containing control and electrical-drive input parameters (quoted string)
"NRELOffshrBsline5MW_OC3Monopile_HydroDyn.dat" HydroFile - Name of file containing hydrodynamic input parameters (quoted string)
"NRELOffshrBsline5MW_OC3Monopile_SubDyn.dat" SubFile - Name of file containing sub-structural input parameters (quoted string)
"unused" MooringFile - Name of file containing mooring system input parameters (quoted string)
"unused" IceFile - Name of file containing ice input parameters (quoted string)
"unused" SoilFile - Name of the file containing the SoilDyn input parameters (quoted string)
------- SERVODYN v1.05.* 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 <RootName>.ech (flag)
"default" DT - Communication interval for controllers (s) (or "default")
---------------------- PITCH CONTROL -------------------------------------------
5 PCMode - Pitch control mode {0: none, 3: user-defined from routine PitchCntrl, 4: user-defined from Simulink/Labview, 5: user-defined from Bladed-style DLL} (switch)
0 TPCOn - Time to enable active pitch control (s) [unused when PCMode=0]
9999.9 TPitManS(1) - Time to start override pitch maneuver for blade 1 and end standard pitch control (s)
9999.9 TPitManS(2) - Time to start override pitch maneuver for blade 2 and end standard pitch control (s)
9999.9 TPitManS(3) - Time to start override pitch maneuver for blade 3 and end standard pitch control (s) [unused for 2 blades]
2 PitManRat(1) - Pitch rate at which override pitch maneuver heads toward final pitch angle for blade 1 (deg/s)
2 PitManRat(2) - Pitch rate at which override pitch maneuver heads toward final pitch angle for blade 2 (deg/s)
2 PitManRat(3) - Pitch rate at which override pitch maneuver heads toward final pitch angle for blade 3 (deg/s) [unused for 2 blades]
0 BlPitchF(1) - Blade 1 final pitch for pitch maneuvers (degrees)
0 BlPitchF(2) - Blade 2 final pitch for pitch maneuvers (degrees)
0 BlPitchF(3) - Blade 3 final pitch for pitch maneuvers (degrees) [unused for 2 blades]
---------------------- GENERATOR AND TORQUE CONTROL ----------------------------
5 VSContrl - Variable-speed control mode {0: none, 1: simple VS, 3: user-defined from routine UserVSCont, 4: user-defined from Simulink/Labview, 5: user-defined from Bladed-style DLL} (switch)
2 GenModel - Generator model {1: simple, 2: Thevenin, 3: user-defined from routine UserGen} (switch) [used only when VSContrl=0]
94.4 GenEff - Generator efficiency [ignored by the Thevenin and user-defined generator models] (%)
True GenTiStr - Method to start the generator {T: timed using TimGenOn, F: generator speed using SpdGenOn} (flag)
True GenTiStp - Method to stop the generator {T: timed using TimGenOf, F: when generator power = 0} (flag)
9999.9 SpdGenOn - Generator speed to turn on the generator for a startup (HSS speed) (rpm) [used only when GenTiStr=False]
0 TimGenOn - Time to turn on the generator for a startup (s) [used only when GenTiStr=True]
9999.9 TimGenOf - Time to turn off the generator (s) [used only when GenTiStp=True]
---------------------- SIMPLE VARIABLE-SPEED TORQUE CONTROL --------------------
9999.9 VS_RtGnSp - Rated generator speed for simple variable-speed generator control (HSS side) (rpm) [used only when VSContrl=1]
9999.9 VS_RtTq - Rated generator torque/constant generator torque in Region 3 for simple variable-speed generator control (HSS side) (N-m) [used only when VSContrl=1]
9999.9 VS_Rgn2K - Generator torque constant in Region 2 for simple variable-speed generator control (HSS side) (N-m/rpm^2) [used only when VSContrl=1]
9999.9 VS_SlPc - Rated generator slip percentage in Region 2 1/2 for simple variable-speed generator control (%) [used only when VSContrl=1]
---------------------- SIMPLE INDUCTION GENERATOR ------------------------------
9999.9 SIG_SlPc - Rated generator slip percentage (%) [used only when VSContrl=0 and GenModel=1]
9999.9 SIG_SySp - Synchronous (zero-torque) generator speed (rpm) [used only when VSContrl=0 and GenModel=1]
9999.9 SIG_RtTq - Rated torque (N-m) [used only when VSContrl=0 and GenModel=1]
9999.9 SIG_PORt - Pull-out ratio (Tpullout/Trated) (-) [used only when VSContrl=0 and GenModel=1]
---------------------- THEVENIN-EQUIVALENT INDUCTION GENERATOR -----------------
9999.9 TEC_Freq - Line frequency [50 or 60] (Hz) [used only when VSContrl=0 and GenModel=2]
9998 TEC_NPol - Number of poles [even integer > 0] (-) [used only when VSContrl=0 and GenModel=2]
9999.9 TEC_SRes - Stator resistance (ohms) [used only when VSContrl=0 and GenModel=2]
9999.9 TEC_RRes - Rotor resistance (ohms) [used only when VSContrl=0 and GenModel=2]
9999.9 TEC_VLL - Line-to-line RMS voltage (volts) [used only when VSContrl=0 and GenModel=2]
9999.9 TEC_SLR - Stator leakage reactance (ohms) [used only when VSContrl=0 and GenModel=2]
9999.9 TEC_RLR - Rotor leakage reactance (ohms) [used only when VSContrl=0 and GenModel=2]
9999.9 TEC_MR - Magnetizing reactance (ohms) [used only when VSContrl=0 and GenModel=2]
---------------------- HIGH-SPEED SHAFT BRAKE ----------------------------------
0 HSSBrMode - HSS brake model {0: none, 1: simple, 3: user-defined from routine UserHSSBr, 4: user-defined from Simulink/Labview, 5: user-defined from Bladed-style DLL} (switch)
9999.9 THSSBrDp - Time to initiate deployment of the HSS brake (s)
0.6 HSSBrDT - Time for HSS-brake to reach full deployment once initiated (sec) [used only when HSSBrMode=1]
28116.2 HSSBrTqF - Fully deployed HSS-brake torque (N-m)
---------------------- NACELLE-YAW CONTROL -------------------------------------
0 YCMode - Yaw control mode {0: none, 3: user-defined from routine UserYawCont, 4: user-defined from Simulink/Labview, 5: user-defined from Bladed-style DLL} (switch)
9999.9 TYCOn - Time to enable active yaw control (s) [unused when YCMode=0]
0 YawNeut - Neutral yaw position--yaw spring force is zero at this yaw (degrees)
9.02832E+09 YawSpr - Nacelle-yaw spring constant (N-m/rad)
1.916E+07 YawDamp - Nacelle-yaw damping constant (N-m/(rad/s))
9999.9 TYawManS - Time to start override yaw maneuver and end standard yaw control (s)
2 YawManRat - Yaw maneuver rate (in absolute value) (deg/s)
0 NacYawF - Final yaw angle for override yaw maneuvers (degrees)
---------------------- AERODYNAMIC FLOW CONTROL --------------------------------
0 AfCmode - Airfoil control mode {0: none, 1: cosine wave cycle, 4: user-defined from Simulink/Labview, 5: user-defined from Bladed-style DLL} (switch)
0 AfC_Mean - Mean level for cosine cycling or steady value (-) [used only with AfCmode==1]
0 AfC_Amp - Amplitude for for cosine cycling of flap signal (-) [used only with AfCmode==1]
0 AfC_Phase - Phase relative to the blade azimuth (0 is vertical) for for cosine cycling of flap signal (deg) [used only with AfCmode==1]
---------------------- STRUCTURAL CONTROL --------------------------------------
0 NumBStC - Number of blade structural controllers (integer)
"unused" BStCfiles - Name of the files for blade structural controllers (quoted strings) [unused when NumBStC==0]
0 NumNStC - Number of nacelle structural controllers (integer)
"unused" NStCfiles - Name of the files for nacelle structural controllers (quoted strings) [unused when NumNStC==0]
0 NumTStC - Number of tower structural controllers (integer)
"unused" TStCfiles - Name of the files for tower structural controllers (quoted strings) [unused when NumTStC==0]
0 NumSStC - Number of substructure structural controllers (integer)
"unused" SStCfiles - Name of the files for substructure structural controllers (quoted strings) [unused when NumSStC==0]
---------------------- CABLE CONTROL -------------------------------------------
0 CCmode - Cable control mode {0: none, 4: user-defined from Simulink/Labview, 5: user-defined from Bladed-style DLL} (switch)
---------------------- BLADED INTERFACE ---------------------------------------- [used only with Bladed Interface]
"../5MW_Baseline/ServoData/DISCON.dll" DLL_FileName - Name/location of the dynamic library {.dll [Windows] or .so [Linux]} in the Bladed-DLL format (-) [used only with Bladed Interface]
"DISCON.IN" DLL_InFile - Name of input file sent to the DLL (-) [used only with Bladed Interface]
"DISCON" DLL_ProcName - Name of procedure in DLL to be called (-) [case sensitive; used only with DLL Interface]
"default" DLL_DT - Communication interval for dynamic library (s) (or "default") [used only with Bladed Interface]
false DLL_Ramp - Whether a linear ramp should be used between DLL_DT time steps [introduces time shift when true] (flag) [used only with Bladed Interface]
9999.9 BPCutoff - Cutoff frequency for low-pass filter on blade pitch from DLL (Hz) [used only with Bladed Interface]
0 NacYaw_North - Reference yaw angle of the nacelle when the upwind end points due North (deg) [used only with Bladed Interface]
0 Ptch_Cntrl - Record 28: Use individual pitch control {0: collective pitch; 1: individual pitch control} (switch) [used only with Bladed Interface]
0 Ptch_SetPnt - Record 5: Below-rated pitch angle set-point (deg) [used only with Bladed Interface]
0 Ptch_Min - Record 6: Minimum pitch angle (deg) [used only with Bladed Interface]
0 Ptch_Max - Record 7: Maximum pitch angle (deg) [used only with Bladed Interface]
0 PtchRate_Min - Record 8: Minimum pitch rate (most negative value allowed) (deg/s) [used only with Bladed Interface]
0 PtchRate_Max - Record 9: Maximum pitch rate (deg/s) [used only with Bladed Interface]
0 Gain_OM - Record 16: Optimal mode gain (Nm/(rad/s)^2) [used only with Bladed Interface]
0 GenSpd_MinOM - Record 17: Minimum generator speed (rpm) [used only with Bladed Interface]
0 GenSpd_MaxOM - Record 18: Optimal mode maximum speed (rpm) [used only with Bladed Interface]
0 GenSpd_Dem - Record 19: Demanded generator speed above rated (rpm) [used only with Bladed Interface]
0 GenTrq_Dem - Record 22: Demanded generator torque above rated (Nm) [used only with Bladed Interface]
0 GenPwr_Dem - Record 13: Demanded power (W) [used only with Bladed Interface]
---------------------- BLADED INTERFACE TORQUE-SPEED LOOK-UP TABLE -------------
0 DLL_NumTrq - Record 26: No. of points in torque-speed look-up table {0 = none and use the optimal mode parameters; nonzero = ignore the optimal mode PARAMETERs by setting Record 16 to 0.0} (-) [used only with Bladed Interface]
GenSpd_TLU GenTrq_TLU
(rpm) (Nm)
------- ELASTODYN for OpenFAST 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 "<RootName>.ech" (flag)
3 Method - Integration method: {1: RK4, 2: AB4, or 3: ABM4} (-)
"default" DT - Integration time step (s)
---------------------- DEGREES OF FREEDOM --------------------------------------
True FlapDOF1 - First flapwise blade mode DOF (flag)
True FlapDOF2 - Second flapwise blade mode DOF (flag)
True EdgeDOF - First edgewise blade mode DOF (flag)
False TeetDOF - Rotor-teeter DOF (flag) [unused for 3 blades]
True DrTrDOF - Drivetrain rotational-flexibility DOF (flag)
True GenDOF - Generator DOF (flag)
True YawDOF - Yaw DOF (flag)
True TwFADOF1 - First fore-aft tower bending-mode DOF (flag)
True TwFADOF2 - Second fore-aft tower bending-mode DOF (flag)
True TwSSDOF1 - First side-to-side tower bending-mode DOF (flag)
True TwSSDOF2 - Second side-to-side tower bending-mode DOF (flag)
True PtfmSgDOF - Platform horizontal surge translation DOF (flag)
True PtfmSwDOF - Platform horizontal sway translation DOF (flag)
True PtfmHvDOF - Platform vertical heave translation DOF (flag)
True PtfmRDOF - Platform roll tilt rotation DOF (flag)
True PtfmPDOF - Platform pitch tilt rotation DOF (flag)
True 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)
0 BlPitch(1) - Blade 1 initial pitch (degrees)
0 BlPitch(2) - Blade 2 initial pitch (degrees)
0 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)
3 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)
-0.0009 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)
-5 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)
10 PtfmCMzt - Vertical distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters)
10 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)
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)
1.534E+06 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 (-)
"../5MW_Baseline/NRELOffshrBsline5MW_Blade.dat" BldFile(1) - Name of file containing properties for blade 1 (quoted string)
"../5MW_Baseline/NRELOffshrBsline5MW_Blade.dat" BldFile(2) - Name of file containing properties for blade 2 (quoted string)
"../5MW_Baseline/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_OC3Monopile_ElastoDyn_Tower.dat" TwrFile - Name of file containing tower properties (quoted string)
(2)How to obtain REDWINmodel2-2.0_x86.dll? I canât find it on Github. Or what resource code can I compile to get it?
Thanks a lot!
Best regards,
Dear @Kevin.Chang,
Perhaps the issue is with the initial conditions you are using? I see that you are modeling the NREL 5-MW baseline wind turbine, but the initial rotor speed (RotSpeed) youâve specified is below the cut-in speed for this turbine. We generally recommend to initialize RotSpeed, as well as the initial blade-pitch angles to their expected (mean) value, conditioned the mean wind speed you are simulating.
The REDWIN DLL was developed by NGI, not NREL, and so, must be obtained through NGI. See the SoilDyn pull request comments for more information: SoilDyn â soil dynamics module by andrew-platt ¡ Pull Request #986 ¡ OpenFAST/openfast ¡ GitHub.
Best regards
Dear NREL Communities
I got a tower strike error during the DLC 6.1 simulation.
I am trying to imitate the result of âTable 12. IEC Design Load Case Matrixâ
(IEA 15MW VolturnUS-S Reference Platform Technical Report: https://www.nrel.gov/docs/fy20osti/76773.pdf, 34 page)
I set âWakeMod = 0â, âAFAeroMod =1â, âPCMode = 0â, âVSContrl = 0â, âGenDOF = Falseâ, âBlPitch(1), (2), (3) = 90â, and âRotSpeed = 0â to simulate a parked condition turbine according to other relevant posts and OpenFAST documentation.
First, I ran the simulation with a yaw error of -8, +8 (IEC DLC 6.1 condition), but a tower strike error occurred.
Second, I ran the simulation without Yaw error, but a tower strike occurred again.
Third, I tried to run simulation with disable âTwFADOF 2â and âTwSSDOF2â following Daniel.Zalkindâs temporary solution in this post, and simulation was finished normally.
I am wondering whether tower model instability or my simulation settings
FYI, I am using OpenFAST v3.5.1, IEA 15MW v1.1.8, ROSCO v2.8, mwLoADS v8.12.
Here are my OpenFAST settings, which I tried first.
- fst
- AeroDynv15
- ElastoDyn
- HydroDyn
- Inflow
- ServoDyn
Best regards,
Sangwon
Hi Sangwon,
Can you share some time-series figures of the OpenFAST outputs? Weâd ideally see the generator speed, blade pitch, out-of-plane tip deflection, and tower top deflection.
Best, Dan
1 Like
Dear @Daniel.Zalkind
This error was caused by my mistake.
I found RotSpeed was set to 7.55.
After I set 0, the simulation was finished normally.
I still have a question about my abnormal results, but this topic is about Tower Strike, so I will post my question on another topic.
Thank you for your kind reply.
Best regards,
Sangwon.
Dear @Jason.Jonkman
When I try to simulate IEA 15MW with OpenFAST+Simulink, I found that as soon as I open the DrTrDOF ,there will be errors.
Could you please tell me why I cannot open the DrTrDOF? Will there exist the torsional motion when I disable DrTrDOF?
Dear @Yinghan.Liu,
The IEA Wind 15-MW reference wind turbine has a direct-drive generator and the shaft is expected to be stiff in torsion, and so, the default way of modeling this turbine in OpenFAST is to keep the DrTrDOF disabled. If you were to enable DrTrDOF, you should define reasonable values of the drivetrain stiffness and damping (DTTorSpr and DTTorDmp), and you would likely need to reduce the time step to capture the likely high frequency of the drivetrain torsional mode.
Best regards,
Dear Jasonďź
For direct drive wind turbine, why do we consider the shaft to be stiff in OpenFAST? Is that because the lack of gearbox enhance the stiff property?
I see that in ElastoDyn.dat file, there are default DTTorSpr and DTTorDmp parameters. Can we use that parameters directly? If we cannot, how do we define reasonable stiffness and damping parameters?
Thank you so much!
---- Replied Message ----
From | Jason Jonkman via NREL Forumnotifications@nrel.discoursemail.com |
- | - |
Date | 04/16/2024 00:33 |
To | camille0327camille0327@126.com |
Subject | [NREL Forum] [Wind & Water/Computer-Aided Engineering Software Tools] Tower strike with latest versions of OpenFAST and IEA 15MW |
| Jason.Jonkman
April 15 |
- | - |
Dear @Yinghan.Liu,
The IEA Wind 15-MW reference wind turbine has a direct-drive generator and the shaft is expected to be stiff in torsion, and so, the default way of modeling this turbine in OpenFAST is to keep the DrTrDOF disabled. If you were to enable DrTrDOF, you should define reasonable values of the drivetrain stiffness and damping (DTTorSpr and DTTorDmp), and you would likely need to reduce the time step to capture the likely high frequency of the drivetrain torsional mode.
Best regards,
Dear @Jason.Jonkman
For direct drive wind turbine, why do we consider the shaft to be stiff in OpenFAST? Is that because the lack of gearbox enhance the stiff property?
I see that in ElastoDyn.dat file, there are default DTTorSpr and DTTorDmp parameters. Can we use that parameters directly? If we cannot, how do we define reasonable stiffness and damping parameters?
Thank you so much!
Dear @Yinghan.Liu,
I was not the one to develop the OpenFAST model of the IEA Wind 15-MW reference wind turbine, but my understanding is that the drivetrain torsion was not modeled because the direct drive shaft was deemed stiff enough that the torsional natural frequency is so high that it would not be excited by aerodynamic loads. Iâm not sure if the values of DTTorSpr and DTTorDmp in the OpenFAST model, which are not used because DrTrDOF = FALSE, are reasonable for this turbine, or are simply carryovers from a different OpenFAST model.
For information on drivetrain properties of the IEA Wind 15-MW reference wind turbine, see the specifications report: https://www.nrel.gov/docs/fy20osti/75698.pdf.
Best regards,
Dear Jason,
Got it!
Thank you so much for your quick reply!
Hello All,
I was having the same error " SetDisturbedInflow:TwrInfl:Tower strike", so I did not want to post somewhere else. I am using AMR-Wind (v.2.1.0) coupled with OpenFAST (v.3.5.0) and ROSCO (v.2.9) for my research. I have a couple of questions so I will post them all here.
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I am using IEA-3.4-130-RWT, and downloaded from [GitHub - IEAWindTask37/IEA-3.4-130-RWT: This repository contains the model data of the land-based reference wind turbine developed within IEA Wind Task 37], my question is that apart from this [[4.1.2. API changes between versions â OpenFAST v3.5.3 documentation] which is very hard for a new user like me to update OpenFAST files with the version, anywhere else instruction to do that and easily explain?
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Previously, I was using AMR-Wind (v.1.0), OpenFAST(v.3.1.0), and ROSCO (v.2.9), and I was having the same âTower Strikeâ problem while using NREL-2p5-116 wind turbine, so I did [âTwrPotent = 0, TwrShadow =0â], then I get âMach number exceeds 1.0â so there is also someone reported the same problem, after looking into the solution from that post I did âAFAeroMod =1, SkewMod =1â, simulation was run for 700s seconds, it completed normally, but having some problem in plotting the AMR-Wind output files, I did all these steps for IEA-3.4-130-RWT but I am getting tower strike after 12s here also.
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Besides this [GitHub - NREL/openfast-turbine-models: A repository of OpenFAST turbine models developed by NREL researchers.] is there anywhere else I can download OpenFAST turbine files for different models?
P.S. I cannot attach files for IEA-3.4-130-RWT, and NREL-2p5-116 in the attachment is there any way to do that, so that an expert can look into it? I have attached a screenshot of the AMR-Wind error file.
Thank you in advance
Asim
Dear @Raja.Asim,
Regarding (1), the IEA Wind 3.4-MW repository says that the model is compatible with v3.5, so, you shouldnât have to upgrade the input files to use this version.
Regarding (3), the IEA Wind Task 37 repository that you linked to contains OpenFAST models of the IEA Wind reference wind turbines. The OpenFAST r-test also contains many sample OpenFAST models including those from the original FAST CertTests and various configurations of the NREL 5-MW baseline wind turbine: r-test/glue-codes/openfast at main ¡ OpenFAST/r-test ¡ GitHub.
Iâm not an expert on the OpenFAST interface to AMR-Wind; Iâll let someone else respond regarding (2).
Best regards,