FastFarm Simulation Errors

[Justin-sudo11]

Hello,I am new to FastFarm and have encountered several error messages during simulation. I cannot figure out the exact causes and which parameters go wrong.
Besides, I would like to consult you:Does the distance between the first row of turbines and the origin X0 affect the turbine output results in wind farm simulation?In other words, similar to SOWFA, do I need to set a sufficient upstream distance to let the incoming wind fully develop before reaching the first row wind turbines?
Thank you very much for your guidance.

FastFarm Error Messages：

**************************************************************************************************
FAST.Farm

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.
**************************************************************************************************

FAST.Farm-v4.2.1
Compile Info:
 - Compiler: Intel(R) Fortran Compiler 20250300
 - Architecture: 64 bit
 - Precision: single
 - OpenMP: No
 - Date: Mar 10 2026
 - Time: 20:16:42
Execution Info:
 - Date: 05/20/2026
 - Time: 19:28:24+0800

 Heading of the FAST.Farm input file:
   Two turbines
 Running AWAE.
 Running InflowWind.

   Reading a 101x35 grid (1000 m wide, 5 m to 345 m above ground) with a characteristic wind
   speed of 11.422 m/s. This full-field file was generated by TurbSim (from OpenFAST-v4.2.1) on
   19-Apr-2026 at 20:45:39.

   Processed 20000 time steps of 20-Hz grid-field data (period of 1000 seconds).
 Running WakeDynamics.
 Running FASTWrapper.
 Running OpenFAST.
OpenFAST input file heading:
    FAST Certification Test #25: NREL 5.0 MW Baseline Wind Turbine with OC4-DeepCwind semi
    configuration, for use in offshore analysis

 Running ElastoDyn.
 Running InflowWind.
 Running SeaState.
 Generating incident wave kinematics and current time history.
 Adjusting incident wave kinematics for turbine offset from array origin.
 Running AeroDyn.
   AeroDyn: projMod: 2
   Projection: Polar, BEM: polar (3D)
 Running HydroDyn.
 Reading in WAMIT output with root name ".\HydroData/marin_semi".
 Computing radiation impulse response functions and wave diffraction forces.
 Calculating second order difference-frequency force using the full quadratic transfer function.
 Calculating second order sum-frequency force using the full quadratic transfer function.
 Running MoorDyn (v2.3.8, 2025-02-27).
   This is MoorDyn v2, with significant input file changes from v1.

**************************************************************************************************
MoorDyn

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.
**************************************************************************************************

  Parsing MoorDyn input file: .\NRELOffshrBsline5MW_OC4DeepCwindSemi_MoorDyn.dat
   Created mooring system:  3 lines, 6 points, 0 rods, 0 bodies.
    Catenary solve of Line 1 unsuccessful. Initializing as linear.
    Catenary solve of Line 2 unsuccessful. Initializing as linear.
    Catenary solve of Line 3 unsuccessful. Initializing as linear.
   Finalizing initial conditions using dynamic relaxation.
   t=46  FairTen 1: 1.10858E+06, 1.10985E+06, 1.11078E+06
   Fairlead tensions converged to 1% after 46 seconds.
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, 7.88651E+05, -6.32181E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: -9.10662E+05, 0, -6.32182E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, -7.88651E+05, -6.32181E+05
  MoorDyn initialization completed.
 Running ServoDyn.
 Running ServoDyn Interface for Bladed Controllers (using Intel Visual Fortran for Windows).
Using legacy Bladed DLL interface.

FAST_InitializeAll:AD_Init:ReadInputFiles:Blade1:ReadBladeInputs:BlCrvAng will be calculated and
overwrite the values specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade2:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade3:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".

 Running OpenFAST.
OpenFAST input file heading:
    FAST Certification Test #25: NREL 5.0 MW Baseline Wind Turbine with OC4-DeepCwind semi
    configuration, for use in offshore analysis

 Running ElastoDyn.
 Running InflowWind.
 Running SeaState.
 Generating incident wave kinematics and current time history.
 Adjusting incident wave kinematics for turbine offset from array origin.
 Running AeroDyn.
   AeroDyn: projMod: 2
   Projection: Polar, BEM: polar (3D)
 Running HydroDyn.
 Reading in WAMIT output with root name ".\HydroData/marin_semi".
 Computing radiation impulse response functions and wave diffraction forces.
 Calculating second order difference-frequency force using the full quadratic transfer function.
 Calculating second order sum-frequency force using the full quadratic transfer function.
 Running MoorDyn (v2.3.8, 2025-02-27).
   This is MoorDyn v2, with significant input file changes from v1.

**************************************************************************************************
MoorDyn

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.
**************************************************************************************************

  Parsing MoorDyn input file: .\NRELOffshrBsline5MW_OC4DeepCwindSemi_MoorDyn.dat
   Created mooring system:  3 lines, 6 points, 0 rods, 0 bodies.
    Catenary solve of Line 1 unsuccessful. Initializing as linear.
    Catenary solve of Line 2 unsuccessful. Initializing as linear.
    Catenary solve of Line 3 unsuccessful. Initializing as linear.
   Finalizing initial conditions using dynamic relaxation.
   t=46  FairTen 1: 1.10858E+06, 1.10985E+06, 1.11078E+06
   Fairlead tensions converged to 1% after 46 seconds.
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, 7.88651E+05, -6.32181E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: -9.10662E+05, 0, -6.32182E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, -7.88651E+05, -6.32181E+05
  MoorDyn initialization completed.
 Running ServoDyn.
 Running ServoDyn Interface for Bladed Controllers (using Intel Visual Fortran for Windows).
Using legacy Bladed DLL interface.

FAST_InitializeAll:AD_Init:ReadInputFiles:Blade1:ReadBladeInputs:BlCrvAng will be calculated and
overwrite the values specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade2:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade3:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".

 Running OpenFAST.
OpenFAST input file heading:
    FAST Certification Test #25: NREL 5.0 MW Baseline Wind Turbine with OC4-DeepCwind semi
    configuration, for use in offshore analysis

 Running ElastoDyn.
 Running InflowWind.
 Running SeaState.
 Generating incident wave kinematics and current time history.
 Adjusting incident wave kinematics for turbine offset from array origin.
 Running AeroDyn.
   AeroDyn: projMod: 2
   Projection: Polar, BEM: polar (3D)
 Running HydroDyn.
 Reading in WAMIT output with root name ".\HydroData/marin_semi".
 Computing radiation impulse response functions and wave diffraction forces.
 Calculating second order difference-frequency force using the full quadratic transfer function.
 Calculating second order sum-frequency force using the full quadratic transfer function.
 Running MoorDyn (v2.3.8, 2025-02-27).
   This is MoorDyn v2, with significant input file changes from v1.

**************************************************************************************************
MoorDyn

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.
**************************************************************************************************

  Parsing MoorDyn input file: .\NRELOffshrBsline5MW_OC4DeepCwindSemi_MoorDyn.dat
   Created mooring system:  3 lines, 6 points, 0 rods, 0 bodies.
    Catenary solve of Line 1 unsuccessful. Initializing as linear.
    Catenary solve of Line 2 unsuccessful. Initializing as linear.
    Catenary solve of Line 3 unsuccessful. Initializing as linear.
   Finalizing initial conditions using dynamic relaxation.
   t=46  FairTen 1: 1.10858E+06, 1.10985E+06, 1.11078E+06
   Fairlead tensions converged to 1% after 46 seconds.
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, 7.88651E+05, -6.32181E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: -9.10662E+05, 0, -6.32182E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, -7.88651E+05, -6.32181E+05
  MoorDyn initialization completed.
 Running ServoDyn.
 Running ServoDyn Interface for Bladed Controllers (using Intel Visual Fortran for Windows).
Using legacy Bladed DLL interface.

FAST_InitializeAll:AD_Init:ReadInputFiles:Blade1:ReadBladeInputs:BlCrvAng will be calculated and
overwrite the values specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade2:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade3:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".

 Time: 0 of 1000 seconds.
The BEM solution is being turned off due to low TSR.  (TSR = 0). This warning will not be
repeated though the condition may persist. (See GeomPhi output channel.)
The BEM solution is being turned off due to low TSR.  (TSR = 0). This warning will not be
repeated though the condition may persist. (See GeomPhi output channel.)
The BEM solution is being turned off due to low TSR.  (TSR = 0). This warning will not be
repeated though the condition may persist. (See GeomPhi output channel.)

T1:FARM_InitialCO:FWrap_t0:FAST_Solution0:CalcOutputs_And_SolveForInputs:SolveOption2:AD_CalcOutpu
t:RotCalcOutput:BEMT_CalcOutput(node 7, blade 1):UA_CalcOutput:UA_BlendSteady:Temporarily turning
off UA due to high angle of attack or low relative velocity. This warning will not be repeated
though the condition may persist.
T2:FARM_InitialCO:FWrap_t0:FAST_Solution0:CalcOutputs_And_SolveForInputs:SolveOption2:AD_CalcOutpu
t:RotCalcOutput:BEMT_CalcOutput(node 7, blade 1):UA_CalcOutput:UA_BlendSteady:Temporarily turning
off UA due to high angle of attack or low relative velocity. This warning will not be repeated
though the condition may persist.
T3:FARM_InitialCO:FWrap_t0:FAST_Solution0:CalcOutputs_And_SolveForInputs:SolveOption2:AD_CalcOutpu
t:RotCalcOutput:BEMT_CalcOutput(node 7, blade 1):UA_CalcOutput:UA_BlendSteady:Temporarily turning
off UA due to high angle of attack or low relative velocity. This warning will not be repeated
though the condition may persist.
 Time: 78 of 1000 seconds.  Estimated final completion at 20:27:17 (in 0.038 days).

T3:FARM_UpdateStates:FWrap_Increment:FAST_Solution:FAST_UpdateStates:FAST_AdvanceStates:AD_UpdateS
tates:BEMT_UpdateStates(node 1, blade 1):ComputeTau:Rotor-averaged axial induction factor is
greater than 0.5; limiting time-varying tau1. This message will not be repeated though the
condition may persist.
 Time: 81 of 1000 seconds.  Estimated final completion at 20:30:17 (in 0.040 days).

T2:FARM_UpdateStates:FWrap_Increment:FAST_Solution:FAST_UpdateStates:FAST_AdvanceStates:AD_UpdateS
tates:BEMT_UpdateStates(node 1, blade 1):ComputeTau:Rotor-averaged axial induction factor is
greater than 0.5; limiting time-varying tau1. This message will not be repeated though the
condition may persist.
 Time: 82 of 1000 seconds.  Estimated final completion at 20:30:24 (in 0.040 days).

T1:FARM_UpdateStates:FWrap_Increment:FAST_Solution:FAST_UpdateStates:FAST_AdvanceStates:AD_UpdateS
tates:BEMT_UpdateStates(node 1, blade 1):ComputeTau:Rotor-averaged axial induction factor is
greater than 0.5; limiting time-varying tau1. This message will not be repeated though the
condition may persist.
 Time: 91 of 1000 seconds.  Estimated final completion at 20:31:50 (in 0.041 days).

T1:FARM_UpdateStates:WD_UpdateStates:NearWakeCorrection:Wake model is not valid in the
propeller-brake region, i.e., Ct > 2.0.



 Aborting FAST.Farm.

PS D:\FastFarm MoreWT Time Compare\Three WT test>

[andrew-platt]

Note: Formatted original question for better readability.

[jjonkman]

Dear @Justin-sudo11,

Regarding the FAST.Farm warnings and error, the first warning I see of significance is the warning about BEM being turned off because TSR = 0. This suggest that you are not initializing your OpenFAST model with a rotor speed that matches its expected value for the mean wind speed you are simulating (as we generally recommend). It appears that you are simulating a set of three NREL 5-MW baseline wind turbines atop OC4-DeepCwind semisubmersibles at a hub-height mean wind speed of around 11.4 m/s; is that correct? For this condition, I would recommend initializing the rotor speed to 12.1 rpm, with a blade pitch of 0degrees. I'd fix that and rerun before worrying about the other warnings and errors.

Regarding the upstream boundary, SOWFA needs the boundary upstream of the rotor to be a sufficient distance to resolve the local rotor blockage. But this same requirement does not exist in FAST.Farm because rotor aerodynamics are solved in OpenFAST through blade-element/momentum theory. So, in FAST.Farm, you should be able to place the upstream wind turbine(s) very close to the upstream boundary.

Best regards,

[Justin-sudo11]

Thank you for your reply @jjonkman . In this simulation, the wind speed at hub height is set to 10 m/s, and I currently set the initial rotor speed to zero. Could you please tell me what proper value I should change it to? Thanks a lot for your guidance.

[jjonkman]

Dear @Justin-sudo11,

The NREL 5-MW baseline wind turbine is documented here: https://docs.nlr.gov/docs/fy09osti/38060.pdf. From Figure 9-1, at 10 m/s, I would initialize the rotor speed to 11.4 rpm.

Best regards,

[Justin-sudo11]

Thank you for your reply @jjonkman . I set the initial rotor speed to 11.4, but I still get the following errors. I am not sure what is causing the problem.

**************************************************************************************************
FAST.Farm

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.
**************************************************************************************************

FAST.Farm-v4.2.1
Compile Info:
 - Compiler: Intel(R) Fortran Compiler 20250300
 - Architecture: 64 bit
 - Precision: single
 - OpenMP: No
 - Date: Mar 10 2026
 - Time: 20:16:42
Execution Info:
 - Date: 05/21/2026
 - Time: 09:03:13+0800

 Heading of the FAST.Farm input file:
   Two turbines
 Running AWAE.
 Running InflowWind.

   Reading a 101x35 grid (1000 m wide, 5 m to 345 m above ground) with a characteristic wind
   speed of 11.422 m/s. This full-field file was generated by TurbSim (from OpenFAST-v4.2.1) on
   19-Apr-2026 at 20:45:39.

   Processed 20000 time steps of 20-Hz grid-field data (period of 1000 seconds).
 Running WakeDynamics.
 Running FASTWrapper.
 Running OpenFAST.
OpenFAST input file heading:
    FAST Certification Test #25: NREL 5.0 MW Baseline Wind Turbine with OC4-DeepCwind semi
    configuration, for use in offshore analysis

 Running ElastoDyn.
 Running InflowWind.
 Running SeaState.
 Generating incident wave kinematics and current time history.
 Adjusting incident wave kinematics for turbine offset from array origin.
 Running AeroDyn.
   AeroDyn: projMod: 2
   Projection: Polar, BEM: polar (3D)
 Running HydroDyn.
 Reading in WAMIT output with root name ".\HydroData/marin_semi".
 Computing radiation impulse response functions and wave diffraction forces.
 Calculating second order difference-frequency force using the full quadratic transfer function.
 Calculating second order sum-frequency force using the full quadratic transfer function.
 Running MoorDyn (v2.3.8, 2025-02-27).
   This is MoorDyn v2, with significant input file changes from v1.

**************************************************************************************************
MoorDyn

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.
**************************************************************************************************

  Parsing MoorDyn input file: .\NRELOffshrBsline5MW_OC4DeepCwindSemi_MoorDyn.dat
   Created mooring system:  3 lines, 6 points, 0 rods, 0 bodies.
    Catenary solve of Line 1 unsuccessful. Initializing as linear.
    Catenary solve of Line 2 unsuccessful. Initializing as linear.
    Catenary solve of Line 3 unsuccessful. Initializing as linear.
   Finalizing initial conditions using dynamic relaxation.
   t=46  FairTen 1: 1.10858E+06, 1.10985E+06, 1.11078E+06
   Fairlead tensions converged to 1% after 46 seconds.
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, 7.88651E+05, -6.32181E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: -9.10662E+05, 0, -6.32182E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, -7.88651E+05, -6.32181E+05
  MoorDyn initialization completed.
 Running ServoDyn.
 Running ServoDyn Interface for Bladed Controllers (using Intel Visual Fortran for Windows).
Using legacy Bladed DLL interface.

FAST_InitializeAll:AD_Init:ReadInputFiles:Blade1:ReadBladeInputs:BlCrvAng will be calculated and
overwrite the values specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade2:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade3:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".

 Running OpenFAST.
OpenFAST input file heading:
    FAST Certification Test #25: NREL 5.0 MW Baseline Wind Turbine with OC4-DeepCwind semi
    configuration, for use in offshore analysis

 Running ElastoDyn.
 Running InflowWind.
 Running SeaState.
 Generating incident wave kinematics and current time history.
 Adjusting incident wave kinematics for turbine offset from array origin.
 Running AeroDyn.
   AeroDyn: projMod: 2
   Projection: Polar, BEM: polar (3D)
 Running HydroDyn.
 Reading in WAMIT output with root name ".\HydroData/marin_semi".
 Computing radiation impulse response functions and wave diffraction forces.
 Calculating second order difference-frequency force using the full quadratic transfer function.
 Calculating second order sum-frequency force using the full quadratic transfer function.
 Running MoorDyn (v2.3.8, 2025-02-27).
   This is MoorDyn v2, with significant input file changes from v1.

**************************************************************************************************
MoorDyn

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.
**************************************************************************************************

  Parsing MoorDyn input file: .\NRELOffshrBsline5MW_OC4DeepCwindSemi_MoorDyn.dat
   Created mooring system:  3 lines, 6 points, 0 rods, 0 bodies.
    Catenary solve of Line 1 unsuccessful. Initializing as linear.
    Catenary solve of Line 2 unsuccessful. Initializing as linear.
    Catenary solve of Line 3 unsuccessful. Initializing as linear.
   Finalizing initial conditions using dynamic relaxation.
   t=46  FairTen 1: 1.10858E+06, 1.10985E+06, 1.11078E+06
   Fairlead tensions converged to 1% after 46 seconds.
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, 7.88651E+05, -6.32181E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: -9.10662E+05, 0, -6.32182E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, -7.88651E+05, -6.32181E+05
  MoorDyn initialization completed.
 Running ServoDyn.
 Running ServoDyn Interface for Bladed Controllers (using Intel Visual Fortran for Windows).
Using legacy Bladed DLL interface.

FAST_InitializeAll:AD_Init:ReadInputFiles:Blade1:ReadBladeInputs:BlCrvAng will be calculated and
overwrite the values specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade2:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade3:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".

 Running OpenFAST.
OpenFAST input file heading:
    FAST Certification Test #25: NREL 5.0 MW Baseline Wind Turbine with OC4-DeepCwind semi
    configuration, for use in offshore analysis

 Running ElastoDyn.
 Running InflowWind.
 Running SeaState.
 Generating incident wave kinematics and current time history.
 Adjusting incident wave kinematics for turbine offset from array origin.
 Running AeroDyn.
   AeroDyn: projMod: 2
   Projection: Polar, BEM: polar (3D)
 Running HydroDyn.
 Reading in WAMIT output with root name ".\HydroData/marin_semi".
 Computing radiation impulse response functions and wave diffraction forces.
 Calculating second order difference-frequency force using the full quadratic transfer function.
 Calculating second order sum-frequency force using the full quadratic transfer function.
 Running MoorDyn (v2.3.8, 2025-02-27).
   This is MoorDyn v2, with significant input file changes from v1.

**************************************************************************************************
MoorDyn

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.
**************************************************************************************************

  Parsing MoorDyn input file: .\NRELOffshrBsline5MW_OC4DeepCwindSemi_MoorDyn.dat
   Created mooring system:  3 lines, 6 points, 0 rods, 0 bodies.
    Catenary solve of Line 1 unsuccessful. Initializing as linear.
    Catenary solve of Line 2 unsuccessful. Initializing as linear.
    Catenary solve of Line 3 unsuccessful. Initializing as linear.
   Finalizing initial conditions using dynamic relaxation.
   t=46  FairTen 1: 1.10858E+06, 1.10985E+06, 1.11078E+06
   Fairlead tensions converged to 1% after 46 seconds.
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, 7.88651E+05, -6.32181E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: -9.10662E+05, 0, -6.32182E+05
   Fairlead tension: 1.10858E+06
   Fairlead forces: 4.55328E+05, -7.88651E+05, -6.32181E+05
  MoorDyn initialization completed.
 Running ServoDyn.
 Running ServoDyn Interface for Bladed Controllers (using Intel Visual Fortran for Windows).
Using legacy Bladed DLL interface.

FAST_InitializeAll:AD_Init:ReadInputFiles:Blade1:ReadBladeInputs:BlCrvAng will be calculated and
overwrite the values specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade2:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade3:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".

 Time: 39 of 1000 seconds.  Estimated final completion at 09:53:15 (in 0.034 days).

T3:FARM_UpdateStates:FWrap_Increment:FAST_Solution:FAST_UpdateStates:FAST_AdvanceStates:AD_UpdateS
tates:BEMT_UpdateStates(node 7, blade 2):UA_UpdateStates:UA_BlendSteadyStates:Temporarily turning
off UA due to high angle of attack or low relative velocity. This warning will not be repeated
though the condition may persist.
 Time: 40 of 1000 seconds.  Estimated final completion at 09:53:19 (in 0.034 days).
The BEM solution is being turned off due to low TSR.  (TSR = 1.9957). This warning will not be
 Time: 53 of 1000 seconds.  Estimated final completion at 09:58:13 (in 0.037 days).

T2:FARM_UpdateStates:FWrap_Increment:FAST_Solution:FAST_UpdateStates:CalcOutputs_And_SolveForInput
s:SolveOption2:AD_CalcOutput:RotCalcOutput:BEMT_CalcOutput(node 7, blade
3):UA_CalcOutput:UA_BlendSteady:Temporarily turning off UA due to high angle of attack or low
relative velocity. This warning will not be repeated though the condition may persist.
 Time: 54 of 1000 seconds.  Estimated final completion at 09:58:56 (in 0.037 days).
The BEM solution is being turned off due to low TSR.  (TSR = 1.9962). This warning will not be
 Time: 88 of 1000 seconds.  Estimated final completion at 10:01:16 (in 0.037 days).

T3:FARM_UpdateStates:WD_UpdateStates:NearWakeCorrection:Wake model is not valid in the
propeller-brake region, i.e., Ct > 2.0.



 Aborting FAST.Farm.


D:\FastFarm MoreWT Time Compare\Three WT>

[andrew-platt]

Can you plot the rotor speeds and blade pitch for all three turbines?

I suspect you have something set incorrectly in ElastoDyn or ServoDyn that is leading to an overspeed.

[Justin-sudo11]

Thanks for your reply @andrew-platt . No output data files are found in the folder, probably due to insufficient simulation time. I attach the ElastoDyn and ServoDyn files for your reference. These files are identical for all three turbines.

------- 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 ".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)
False 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)
11.4 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)
-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 relative to ground level [onshore], MSL [offshore wind or floating MHK], or seabed [fixed MHK] (meters)
10 TowerBsHt - Height of tower base relative to ground level [onshore], MSL [offshore wind or floating MHK], or seabed [fixed MHK] (meters)
0 PtfmCMxt - Downwind distance from the ground level [onshore], MSL [offshore wind or floating MHK], or seabed [fixed MHK] to the platform CM (meters)
0 PtfmCMyt - Lateral distance from the ground level [onshore], MSL [offshore wind or floating MHK], or seabed [fixed MHK] to the platform CM (meters)
-8.6588 PtfmCMzt - Vertical distance from the ground level [onshore], MSL [offshore wind or floating MHK], or seabed [fixed MHK] to the platform CM (meters)
0 PtfmRefzt - Vertical distance from the ground level [onshore], MSL [offshore wind or floating MHK], or seabed [fixed MHK] 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 (2 or 3-blades) (kg m^2)
0 HubIner_Teeter - Hub inertia about teeter axis (2-blades) (kg m^2)
534.116 GenIner - Generator inertia about HSS (kg m^2)
240000 NacMass - Nacelle mass (kg)
2607890 NacYIner - Nacelle inertia about yaw axis (kg m^2)
0 YawBrMass - Yaw bearing mass (kg)
3852180 PtfmMass - Platform mass (kg)
2.56193E+09 PtfmRIner - Platform inertia for roll tilt rotation about the platform CM (kg m^2)
2.56193E+09 PtfmPIner - Platform inertia for pitch tilt rotation about the platform CM (kg m^2)
4.24265E+09 PtfmYIner - Platform inertia for yaw rotation about the platform CM (kg m^2)
0 PtfmXYIner - Platform xy moment of inertia about the platform CM (=-int(xydm)) (kg m^2)
0 PtfmYZIner - Platform yz moment of inertia about the platform CM (=-int(yzdm)) (kg m^2)
0 PtfmXZIner - Platform xz moment of inertia about the platform CM (=-int(xzdm)) (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]
---------------------- YAW-FRICTION --------------------------------------------
0 YawFrctMod - Yaw-friction model {0: none, 1: friction independent of yaw-bearing force and bending moment, 2: friction with Coulomb terms depending on yaw-bearing force and bending moment, 3: user defined model} (switch)
300 M_CSmax - Maximum static Coulomb friction torque (N-m) [M_CSmax when YawFrctMod=1; |Fz|*M_CSmax when YawFrctMod=2 and Fz<0]
0 M_FCSmax - Maximum static Coulomb friction torque proportional to yaw bearing shear force (N-m) [sqrt(Fx^2+Fy^2)*M_FCSmax; only used when YawFrctMod=2]
0 M_MCSmax - Maximum static Coulomb friction torque proportional to yaw bearing bending moment (N-m) [sqrt(Mx^2+My^2)*M_MCSmax; only used when YawFrctMod=2]
40 M_CD - Dynamic Coulomb friction moment (N-m) [M_CD when YawFrctMod=1; |Fz|*M_CD when YawFrctMod=2 and Fz<0]
0 M_FCD - Dynamic Coulomb friction moment proportional to yaw bearing shear force (N-m) [sqrt(Fx^2+Fy^2)*M_FCD; only used when YawFrctMod=2]
0 M_MCD - Dynamic Coulomb friction moment proportional to yaw bearing bending moment (N-m) [sqrt(Mx^2+My^2)*M_MCD; only used when YawFrctMod=2]
0 sig_v - Linear viscous friction coefficient (N-m/(rad/s))
0 sig_v2 - Quadratic viscous friction coefficient (N-m/(rad/s)^2)
0 OmgCut - Yaw angular velocity cutoff below which viscous friction is linearized (rad/s)
---------------------- DRIVETRAIN ----------------------------------------------
100 GBoxEff - Gearbox efficiency (%)
97 GBRatio - Gearbox ratio (-)
867637000 DTTorSpr - Drivetrain torsional spring (N-m/rad)
6215000 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_OC4DeepCwindSemi_ElastoDyn_Tower.dat" TwrFile - Name of file containing tower properties (quoted string)
---------------------- OUTPUT --------------------------------------------------
False SumPrint - Print summary data to ".sum" (flag)
2 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)
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]
OutList - The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, (-)
"Azimuth" - Blade 1 azimuth angle
"RotSpeed" - Low-speed shaft speed
"GenSpeed" - High-speed shaft speed
"OoPDefl1" - Blade 1 out-of-plane deflection
"IPDefl1" - Blade 1 in-plane deflection
"TwstDefl1" - Blade 1 tip twist
"BldPitch1" - Blade 1 pitch angle
"TTDspFA" - Tower fore-aft deflection
"TTDspSS" - Tower side-to-side deflection
"TTDspTwst" - Tower top twist
"PtfmSurge" - Platform translational surge displacement
"PtfmSway" - Platform translational sway displacement
"PtfmHeave" - Platform translational heave displacement
"PtfmRoll" - Platform rotational roll displacement
"PtfmPitch" - Platform rotational pitch displacement
"PtfmYaw" - Platform rotational yaw displacement
"RootFxc1" - Out-of-plane shear force at the root of blade 1
"RootFyc1" - In-plane shear force at the root of blade 1
"RootFzc1" - Axial force at the root of blade 1
"RootMxc1" - In-plane bending moment at the root of blade 1
"RootMyc1" - Out-of-plane bending moment at the root of blade 1
"RootMzc1" - Pitching moment at the root of blade 1
"RootMxb1"
"RootMyb1"
"RotPwr"
"RotThrust"
"RotTorq" - Rotor torque
"LSSGagMya" - Low-speed shaft 0- rotating bending moments at the main bearing
"LSSGagMza" - Low-speed shaft 90-rotating bending moments at the main bearing
"YawBrFxp" - Fore-aft shear force at the top of the tower (not rotating with nacelle yaw)
"YawBrFyp" - Side-to-side shear force at the top of the tower (not rotating with nacelle yaw)
"YawBrFzp" - Vertical force at the top of the tower (not rotating with nacelle yaw)
"YawBrMxp" - Side-to-side bending moment at the top of the tower (not rotating with nacelle yaw)
"YawBrMyp" - Fore-aft bending moment at the top of the tower (not rotating with nacelle yaw)
"YawBrMzp" - Yaw moment at the top of the tower (not rotating with nacelle yaw)
"TwrBsFxt" - Fore-aft shear force at the base of the tower (platform)
"TwrBsFyt" - Side-to-side shear force at the base of the tower (platform)
"TwrBsFzt" - Vertical force at the base of the tower (platform)
"TwrBsMxt" - Side-to-side bending moment at the base of the tower (platform)
"TwrBsMyt" - Fore-aft bending moment at the base of the tower (platform)
"TwrBsMzt" - Yaw moment at the base of the tower (platform)
END of OutList section (the word "END" must appear in the first 3 columns of the last OutList line)
====== Outputs for all blade stations (same ending as above for Spn1.... =========================== [optional section]
1 BldNd_BladesOut - Number of blades to output all node information at. Up to number of blades on turbine. (-)
"All" BldNd_BlOutNd - Future feature will allow selecting a portion of the nodes to output. Not implemented yet. (-)
OutList - The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, (-)
END (the word "END" must appear in the first 3 columns of this last OutList line in the optional nodal output section)

------- SERVODYN 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)
"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]
8 PitManRat(1) - Pitch rate at which override pitch maneuver heads toward final pitch angle for blade 1 (deg/s)
8 PitManRat(2) - Pitch rate at which override pitch maneuver heads toward final pitch angle for blade 2 (deg/s)
8 PitManRat(3) - Pitch rate at which override pitch maneuver heads toward final pitch angle for blade 3 (deg/s) [unused for 2 blades]
90 BlPitchF(1) - Blade 1 final pitch for pitch maneuvers (degrees)
90 BlPitchF(2) - Blade 2 final pitch for pitch maneuvers (degrees)
90 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)
19160000 YawDamp - Nacelle-yaw damping constant (N-m/(rad/s))
9999.9 TYawManS - Time to start override yaw maneuver and end standard yaw control (s)
0.3 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]
"Discon_OC3HywindT1.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)
---------------------- OUTPUT --------------------------------------------------
False SumPrint - Print summary data to .sum (flag) (currently unused)
2 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)
OutList - The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, (-)
"GenPwr" - Electrical generator power
"GenTq" - Electrical generator torque
END of ServoDyn input file (the word "END" must appear in the first 3 columns of this last line).

[andrew-platt]

I don't see anything immediately obvious from these files. For the output, you can change the OutFileFmt to 1 in your .fst files to get output as the simulation runs.

Do your ServoDynT2 and ServoDynT3 point to the corresponding controller DLLs? We've seen a few instances where the same DLL gets called by all turbines creating some strange results.

[Justin-sudo11]

Thank you for your reply. @andrew-platt
After re-running the simulation, it only ran for 88 seconds and then stopped. I cannot open the result files with visualization software, and I am not sure what caused this issue.
In addition, each turbine uses its own separate ElastoDyn file, ServoDyn file, and DLL file.
Thank you very much for your help.

---

FAST.Farm

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.

---

FAST.Farm-v4.2.1
Compile Info:

• Compiler: Intel(R) Fortran Compiler 20250300
• Architecture: 64 bit
• Precision: single
• OpenMP: No
• Date: Mar 10 2026
• Time: 20:16:42
  Execution Info:
• Date: 05/21/2026
• Time: 23:48:25+0800

Heading of the FAST.Farm input file:
Two turbines
Running AWAE.
Running InflowWind.

Reading a 101x35 grid (1000 m wide, 5 m to 345 m above ground) with a characteristic wind
speed of 11.422 m/s. This full-field file was generated by TurbSim (from OpenFAST-v4.2.1) on
19-Apr-2026 at 20:45:39.

Processed 20000 time steps of 20-Hz grid-field data (period of 1000 seconds).
Running WakeDynamics.
Running FASTWrapper.
Running OpenFAST.
OpenFAST input file heading:
FAST Certification Test #25: NREL 5.0 MW Baseline Wind Turbine with OC4-DeepCwind semi
configuration, for use in offshore analysis

Running ElastoDyn.
Running InflowWind.
Running SeaState.
Generating incident wave kinematics and current time history.
Adjusting incident wave kinematics for turbine offset from array origin.
Running AeroDyn.
AeroDyn: projMod: 2
Projection: Polar, BEM: polar (3D)
Running HydroDyn.
Reading in WAMIT output with root name ".\HydroData/marin_semi".
Computing radiation impulse response functions and wave diffraction forces.
Calculating second order difference-frequency force using the full quadratic transfer function.
Calculating second order sum-frequency force using the full quadratic transfer function.
Running MoorDyn (v2.3.8, 2025-02-27).
This is MoorDyn v2, with significant input file changes from v1.

---

MoorDyn

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.

---

Parsing MoorDyn input file: .\NRELOffshrBsline5MW_OC4DeepCwindSemi_MoorDyn.dat
Created mooring system: 3 lines, 6 points, 0 rods, 0 bodies.
Catenary solve of Line 1 unsuccessful. Initializing as linear.
Catenary solve of Line 2 unsuccessful. Initializing as linear.
Catenary solve of Line 3 unsuccessful. Initializing as linear.
Finalizing initial conditions using dynamic relaxation.
t=46 FairTen 1: 1.10858E+06, 1.10985E+06, 1.11078E+06
Fairlead tensions converged to 1% after 46 seconds.
Fairlead tension: 1.10858E+06
Fairlead forces: 4.55328E+05, 7.88651E+05, -6.32181E+05
Fairlead tension: 1.10858E+06
Fairlead forces: -9.10662E+05, 0, -6.32182E+05
Fairlead tension: 1.10858E+06
Fairlead forces: 4.55328E+05, -7.88651E+05, -6.32181E+05
MoorDyn initialization completed.
Running ServoDyn.
Running ServoDyn Interface for Bladed Controllers (using Intel Visual Fortran for Windows).
Using legacy Bladed DLL interface.

FAST_InitializeAll:AD_Init:ReadInputFiles:Blade1:ReadBladeInputs:BlCrvAng will be calculated and
overwrite the values specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade2:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade3:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".

Running OpenFAST.
OpenFAST input file heading:
FAST Certification Test #25: NREL 5.0 MW Baseline Wind Turbine with OC4-DeepCwind semi
configuration, for use in offshore analysis

Running ElastoDyn.
Running InflowWind.
Running SeaState.
Generating incident wave kinematics and current time history.
Adjusting incident wave kinematics for turbine offset from array origin.
Running AeroDyn.
AeroDyn: projMod: 2
Projection: Polar, BEM: polar (3D)
Running HydroDyn.
Reading in WAMIT output with root name ".\HydroData/marin_semi".
Computing radiation impulse response functions and wave diffraction forces.
Calculating second order difference-frequency force using the full quadratic transfer function.
Calculating second order sum-frequency force using the full quadratic transfer function.
Running MoorDyn (v2.3.8, 2025-02-27).
This is MoorDyn v2, with significant input file changes from v1.

---

MoorDyn

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.

---

Parsing MoorDyn input file: .\NRELOffshrBsline5MW_OC4DeepCwindSemi_MoorDyn.dat
Created mooring system: 3 lines, 6 points, 0 rods, 0 bodies.
Catenary solve of Line 1 unsuccessful. Initializing as linear.
Catenary solve of Line 2 unsuccessful. Initializing as linear.
Catenary solve of Line 3 unsuccessful. Initializing as linear.
Finalizing initial conditions using dynamic relaxation.
t=46 FairTen 1: 1.10858E+06, 1.10985E+06, 1.11078E+06
Fairlead tensions converged to 1% after 46 seconds.
Fairlead tension: 1.10858E+06
Fairlead forces: 4.55328E+05, 7.88651E+05, -6.32181E+05
Fairlead tension: 1.10858E+06
Fairlead forces: -9.10662E+05, 0, -6.32182E+05
Fairlead tension: 1.10858E+06
Fairlead forces: 4.55328E+05, -7.88651E+05, -6.32181E+05
MoorDyn initialization completed.
Running ServoDyn.
Running ServoDyn Interface for Bladed Controllers (using Intel Visual Fortran for Windows).
Using legacy Bladed DLL interface.

FAST_InitializeAll:AD_Init:ReadInputFiles:Blade1:ReadBladeInputs:BlCrvAng will be calculated and
overwrite the values specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade2:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade3:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".

Running OpenFAST.
OpenFAST input file heading:
FAST Certification Test #25: NREL 5.0 MW Baseline Wind Turbine with OC4-DeepCwind semi
configuration, for use in offshore analysis

Running ElastoDyn.
Running InflowWind.
Running SeaState.
Generating incident wave kinematics and current time history.
Adjusting incident wave kinematics for turbine offset from array origin.
Running AeroDyn.
AeroDyn: projMod: 2
Projection: Polar, BEM: polar (3D)
Running HydroDyn.
Reading in WAMIT output with root name ".\HydroData/marin_semi".
Computing radiation impulse response functions and wave diffraction forces.
Calculating second order difference-frequency force using the full quadratic transfer function.
Calculating second order sum-frequency force using the full quadratic transfer function.
Running MoorDyn (v2.3.8, 2025-02-27).
This is MoorDyn v2, with significant input file changes from v1.

---

MoorDyn

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.

---

Parsing MoorDyn input file: .\NRELOffshrBsline5MW_OC4DeepCwindSemi_MoorDyn.dat
Created mooring system: 3 lines, 6 points, 0 rods, 0 bodies.
Catenary solve of Line 1 unsuccessful. Initializing as linear.
Catenary solve of Line 2 unsuccessful. Initializing as linear.
Catenary solve of Line 3 unsuccessful. Initializing as linear.
Finalizing initial conditions using dynamic relaxation.
t=46 FairTen 1: 1.10858E+06, 1.10985E+06, 1.11078E+06
Fairlead tensions converged to 1% after 46 seconds.
Fairlead tension: 1.10858E+06
Fairlead forces: 4.55328E+05, 7.88651E+05, -6.32181E+05
Fairlead tension: 1.10858E+06
Fairlead forces: -9.10662E+05, 0, -6.32182E+05
Fairlead tension: 1.10858E+06
Fairlead forces: 4.55328E+05, -7.88651E+05, -6.32181E+05
MoorDyn initialization completed.
Running ServoDyn.
Running ServoDyn Interface for Bladed Controllers (using Intel Visual Fortran for Windows).
Using legacy Bladed DLL interface.

FAST_InitializeAll:AD_Init:ReadInputFiles:Blade1:ReadBladeInputs:BlCrvAng will be calculated and
overwrite the values specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade2:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".
ReadInputFiles:Blade3:ReadBladeInputs:BlCrvAng will be calculated and overwrite the values
specified in blade file ".\NRELOffshrBsline5MW_AeroDyn_blade.dat".

Time: 39 of 1000 seconds. Estimated final completion at 00:28:51 (in 0.027 days).

T3:FARM_UpdateStates:FWrap_Increment:FAST_Solution:FAST_UpdateStates:FAST_AdvanceStates:AD_UpdateS
tates:BEMT_UpdateStates(node 7, blade 2):UA_UpdateStates:UA_BlendSteadyStates:Temporarily turning
off UA due to high angle of attack or low relative velocity. This warning will not be repeated
though the condition may persist.
Time: 40 of 1000 seconds. Estimated final completion at 00:28:36 (in 0.027 days).
The BEM solution is being turned off due to low TSR. (TSR = 1.9957). This warning will not be
Time: 53 of 1000 seconds. Estimated final completion at 00:33:34 (in 0.030 days).

T2:FARM_UpdateStates:FWrap_Increment:FAST_Solution:FAST_UpdateStates:CalcOutputs_And_SolveForInput
s:SolveOption2:AD_CalcOutput:RotCalcOutput:BEMT_CalcOutput(node 7, blade
3):UA_CalcOutput:UA_BlendSteady:Temporarily turning off UA due to high angle of attack or low
relative velocity. This warning will not be repeated though the condition may persist.
Time: 54 of 1000 seconds. Estimated final completion at 00:33:49 (in 0.030 days).
The BEM solution is being turned off due to low TSR. (TSR = 1.9962). This warning will not be
Time: 88 of 1000 seconds. Estimated final completion at 00:44:58 (in 0.037 days).

T3:FARM_UpdateStates:WD_UpdateStates:NearWakeCorrection:Wake model is not valid in the
propeller-brake region, i.e., Ct > 2.0.

Aborting FAST.Farm.

[jjonkman]

Dear @Justin-sudo11,

I'm not sure why your output file is empty. If you haven't already and to debug what is going on, I suggesting outputting the time series data starting at time zero by setting TStart = 0 s in each OpenFAST model's primary (fst) input file for the turbine-related outputs, as well as TStart = 0 s in the FAST.Farm input (fstf) file FAST.Farms-specific outputs.

Best regards,

[Justin-sudo11]

Thanks for your guidance @jjonkman. I set TStart to 0 as suggested, and plotted the curves of rotor speed and blade pitch angle.