Dear Dr. Jonkman,
Hope you’re doing well. I’m a new OpenFAST user with limited experience in compiling source code, and I encountered a distinct fatal initialization error when running the public IEA 15 MW VolturnUS-S semi-submersible floating wind turbine benchmark model.
The openfast.exe file used in the calculation process is downloaded directly from the Release on Github (https://github.com/OpenFAST/openfast/releases/tag/v5.0.0.) I compared two different versions of OpenFast software and found that neither of them could calculate successfully.
Here are the detailed output results:
When calculating with OpenFAST-v4.1.0,
1）the information displayed in the cmd window is:
E:\FAST\OpenFAST\reg_tests\r-test\glue-codes\openfast\15MW_IEA-15-240-RWT-UMaineSemi>openfast_x64.exe IEA-15-240-RWT-UMaineSemi.fst
OpenFAST
Copyright (C) 2025 National Renewable Energy Laboratory
Copyright (C) 2025 Envision Energy USA LTD
This program is licensed under Apache License Version 2.0 and comes with ABSOLUTELY NO WARRANTY.
See the “LICENSE” file distributed with this software for details.
OpenFAST-v4.1.0
Compile Info:
- Compiler: Intel(R) Fortran Compiler 2021
- Architecture: 64 bit
- Precision: single
- OpenMP: No
- Date: Jun 19 2025
- Time: 03:54:01
Execution Info:
- Date: 06/04/2026
- Time: 20:50:47+0800
OpenFAST input file heading:
IEA 15 MW offshore reference model on UMaine VolturnUS-S semi-submersible floating platform
Running ElastoDyn.
FAST_InitializeAll:ED_Init:ED_ReadInput:ReadPrimaryFile:Invalid numerical input for file
“.\IEA-15-240-RWT-UMaineSemi_ElastoDyn.dat” occurred while trying to read BldNodes.
OpenFAST encountered an error during module initialization.
Simulation error level: FATAL ERROR
Aborting OpenFAST.
2）The corresponding content in the. ech file is:
This file of echoed input was generated by OpenFAST on 04-Jun-2026 at 20:50:47.
Data from OpenFAST primary input file “IEA-15-240-RWT-UMaineSemi.fst”:
------- OpenFAST INPUT FILE -------------------------------------------
FTitle - File Header: File Description (line 2)
“IEA 15 MW offshore reference model on UMaine VolturnUS-S semi-submersible floating platform”
---------------------- SIMULATION CONTROL --------------------------------------
T Echo - Echo input data to .ech (flag)
AbortLevel - Error level when simulation should abort (string)
“FATAL”
1.0000E+01 TMax - Total run time (s)
2.5000E-02 DT - Recommended module time step (s)
2 InterpOrder - Interpolation order for inputs and outputs {0=nearest neighbor ,1=linear, 2=quadratic} (-)
0 NumCrctn - Number of corrections{0=explicit calculation, i.e., no corrections} (-)
9.9999E+04 DT_UJac - Time between calls to get Jacobians (s)
1.0000E+06 UJacSclFact - Scaling factor used in Jacobians (-)
---------------------- FEATURE SWITCHES AND FLAGS ------------------------------
1 CompElast - Compute structural dynamics (switch) {1=ElastoDyn; 2=ElastoDyn + BeamDyn for blades; 3=Simplified-ElastoDyn}
1 CompInflow - inflow wind velocities (switch) {0=still air; 1=InflowWind}
2 CompAero - Compute aerodynamic loads (switch) {0=None; 1=AeroDisk; 2=AeroDyn; 3=ExtLoads}
1 CompServo - Compute control and electrical-drive dynamics (switch) {0=None; 1=ServoDyn}
1 CompSeaSt - Compute sea state information (switch) {0=None; 1=SeaState}}
1 CompHydro - Compute hydrodynamic loads (switch) {0=None; 1=HydroDyn}
0 CompSub - Compute sub-structural dynamics (switch) {0=None; 1=SubDyn}
3 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}
0 MHK - MHK turbine type (switch) {0=Not an MHK turbine; 1=Fixed MHK turbine; 2=Floating MHK turbine}
---------------------- ENVIRONMENTAL CONDITIONS --------------------------------
9.8100E+00 Gravity - Gravitational acceleration (m/s^2)
1.2250E+00 AirDens - Air density (kg/m^3)
1.0250E+03 WtrDens - Water density (kg/m^3)
1.4640E-05 KinVisc - Kinematic viscosity of working fluid (m^2/s)
3.3500E+02 SpdSound - Speed of sound in working fluid (m/s)
1.0350E+05 Patm - Atmospheric pressure ¶
1.7000E+03 Pvap - Vapour pressure of working fluid ¶
2.0000E+02 WtrDpth - Water depth (m)
0.0000E+00 MSL2SWL - Offset between still-water level and mean sea level (m)
---------------------- INPUT FILES ---------------------------------------------
EDFile - Name of file containing ElastoDyn input parameters (-)
“IEA-15-240-RWT-UMaineSemi_ElastoDyn.dat”
BDBldFile(1) - Name of file containing BeamDyn blade 1input parameters (-)
“”
BDBldFile(2) - Name of file containing BeamDyn blade 2input parameters (-)
“”
BDBldFile(3) - Name of file containing BeamDyn blade 3input parameters (-)
“”
InflowFile - Name of file containing inflow wind input parameters (-)
“../IEA-15-240-RWT/IEA-15-240-RWT_InflowFile.dat”
AeroFile - Name of file containing aerodynamic input parameters (-)
“IEA-15-240-RWT-UMaineSemi_AeroDyn15.dat”
ServoFile - Name of file containing control and electrical-drive input parameters (-)
“IEA-15-240-RWT-UMaineSemi_ServoDyn.dat”
SeaStFile - Name of file containing sea state input parameters (-)
“IEA-15-240-RWT-UMaineSemi_SeaState.dat”
HydroFile - Name of file containing hydrodynamic input parameters (-)
“IEA-15-240-RWT-UMaineSemi_HydroDyn.dat”
SubFile - Name of file containing sub-structural input parameters (-)
“none”
MooringFile - Name of file containing mooring system input parameters (-)
“IEA-15-240-RWT-UMaineSemi_MoorDyn.dat”
IceFile - Name of file containing ice input parameters (-)
“none”
---------------------- OUTPUT --------------------------------------------------
F SumPrint - Print summary data to .sum (flag)
1.0000E+01 SttsTime - Amount of time between screen status messages (s)
9.9999E+04 ChkptTime - Amount of time between creating checkpoint files for potential restart (s)
DT_Out - Time step for tabular output (s)
“default”
0.0000E+00 TStart - Time to begin tabular output (s)
2 OutFileFmt - Format for tabular (time-marching) output file(s) {0: uncompressed binary and text file, 1: text file [.out], 2: compressed binary file [.outb], 3: both text and compressed binary, 4: uncompressed binary .outb]; add for combinations) (-)
T TabDelim - Use tab delimiters in text tabular output file? (flag)
OutFmt - Format used for text tabular output (except time). Resulting field should be 10 characters. (-)
“ES10.3E2”
---------------------- LINEARIZATION -------------------------------------------
F Linearize - Linearization analysis (flag)
F CalcSteady - Calculate a steady-state periodic operating point before linearization? (flag)
3 TrimCase - Controller parameter to be trimmed {1:yaw; 2:torque; 3:pitch} (-)
1.0000E-03 TrimTol - Tolerance for the rotational speed convergence (-)
1.0000E-02 TrimGain - Proportional gain for the rotational speed error (>0) (rad/(rad/s) for yaw or pitch; Nm/(rad/s) for torque)
0.0000E+00 Twr_Kdmp - Damping factor for the tower (N/(m/s))
0.0000E+00 Bld_Kdmp - Damping factor for the blades (N/(m/s))
2 NLinTimes - Number of times to linearize (-) [>=1]
30.000000, 60.000000 LinTimes - List of times at which to linearize (s) [1 to NLinTimes] [used only when Linearize=True and CalcSteady=False]
1 LinInputs - Include inputs in linearization (switch) {0=none; 1=standard; 2=all module inputs (debug)}
1 LinOutputs - Include outputs in linearization (switch) (0=none; 1=from OutList(s); 2=all module outputs (debug))
F LinOutJac - Include full Jacabians in linearization output (for debug) (flag)
F LinOutMod - Write module-level linearization output files in addition to output for full system? (flag)
---------------------- VISUALIZATION ------------------------------------------
0 WrVTK - Write VTK visualization files (0=none; 1=initialization data only; 2=animation; 3=mode shapes)
2 VTK_Type - Type of VTK visualization data: (1=surfaces; 2=basic meshes (lines/points); 3=all meshes)
F VTK_fields - Write mesh fields to VTK data files? (flag)
1.5000E+01 VTK_fps - Frame rate for VTK output(fps)
When calculating with OpenFAST-v5.0.0,
1）the information displayed in the cmd window is:
E:\FAST\OpenFAST\reg_tests\r-test\glue-codes\openfast\15MW_IEA-15-240-RWT-UMaineSemi>OpenFAST.exe IEA-15-240-RWT-UMaineSemi.fst
OpenFAST
Copyright (C) 2026 National Renewable Energy Laboratory
Copyright (C) 2026 Envision Energy USA LTD
This program is licensed under Apache License Version 2.0 and comes with ABSOLUTELY NO WARRANTY.
See the “LICENSE” file distributed with this software for details.
OpenFAST-v5.0.0
Compile Info:
- Compiler: Intel(R) Fortran Compiler 20250302
- Architecture: 64 bit
- Precision: single
- OpenMP: No
- Date: Mar 13 2026
- Time: 19:00:22
Execution Info:
- Date: 06/04/2026
- Time: 20:47:28+0800
OpenFAST input file heading:
IEA 15 MW offshore reference model on UMaine VolturnUS-S semi-submersible floating platform
FAST_InitializeAll:FAST_Init:FAST_ReadPrimaryFile:Invalid numerical input for file
“IEA-15-240-RWT-UMaineSemi.fst” occurred while trying to read ConvTol.
OpenFAST encountered an error during module initialization.
Simulation error level: FATAL ERROR
Aborting OpenFAST.
2）The corresponding content in the. ech file is:
This file of echoed input was generated by OpenFAST on 04-Jun-2026 at 20:47:28.
Data from OpenFAST primary input file “IEA-15-240-RWT-UMaineSemi.fst”:
------- OpenFAST INPUT FILE -------------------------------------------
FTitle - File Header: File Description (line 2)
“IEA 15 MW offshore reference model on UMaine VolturnUS-S semi-submersible floating platform”
---------------------- SIMULATION CONTROL --------------------------------------
T Echo - Echo input data to .ech (flag)
AbortLevel - Error level when simulation should abort (string)
“FATAL”
1.0000E+01 TMax - Total run time (s)
2.5000E-02 DT - Recommended module time step (s)
2 ModCoupling - Module coupling method (switch) {1=loose; 2=tight with fixed Jacobian updates (DT_UJac); 3=tight with automatic Jacobian updates}
0 InterpOrder - Interpolation order for inputs and outputs {0=nearest neighbor ,1=linear, 2=quadratic} (-)
99999 NumCrctn - Number of corrections{0=explicit calculation, i.e., no corrections} (-)
1.0000E+06 RhoInf - Numerical damping parameter for tight coupling generalized-alpha integrator (-) [0.0 to 1.0]
Thank you very much for your assistance.
Best regards, Ziqin Zhong