### Simulation errors of MIT NREL TLP (Test 23)

Posted:

**Thu Jun 04, 2020 2:28 pm**Dear all,

I was trying to run the simulation using Test 23 files and got some problems.

I used the environmental condition used for model validation in https://www.nrel.gov/docs/fy10osti/45891.pdf (Denis's PhD thesis): 11 m/s hub-height wind speed, 10-m significant wave height and Tp of 17.64s. Based on the inital files, I made the following modifications:

In ElastoDyn, I disabled all the other DoFs except for the last six for the platform motion. RotSpeed was set to zero and BlPitch(i) were set to 90 in order to model the parked turbine state.

In HydroDyn, I changed WaveHs to 10 and WaveTp tp 17.64 and WaveDir to 0.

In AeroDyn, I raised the first aerodynamic node to 10m above the SWL and set WakeMod to zero.

In ServoDyn, I turned off the generator.

Besides, I extend the simulation time in fst file and HydroDyn file to 10800 s (3h) and increased Dt to 0.25.

I got the following error messeges:

FAST_Solution:CalcOutputs_And_SolveForInputs:SolveOption1:ED_HD_InputOutputSolve:HydroDyn_CalcOutp

ut: Angles in GetSmllRotAngs() are larger than 0.4 radians.

ED_HD_InputOutputSolve:HydroDyn_CalcOutput: Angles in GetSmllRotAngs() are larger than 0.4

radians.

FAST_Solution:CalcOutputs_And_SolveForInputs:SolveOption2:InflowWind_CalcOutput:CalcOutput:IfW_Uni

formWind_CalcOutput:GetWindSpeed:Height must not be negative.

IfW_UniformWind_CalcOutput: Error calculating the wind speed at position (-4.31086E+09,

2.42859E+09, -4.99252E+09) in the wind-file coordinates

CalcOutputs_And_SolveForInputs:SolveOption1:ED_HD_InputOutputSolve:HydroDyn_CalcOutput: Angles in

GetSmllRotAngs() are larger than 0.4 radians.

ED_HD_InputOutputSolve:HydroDyn_CalcOutput: Angles in GetSmllRotAngs() are larger than 0.4

radians.

FAST encountered an error at simulation time 7.75 of 10800 seconds.

Simulation error level: FATAL ERROR

Aborting FAST.

I think FAST is capable of simulating the model under the environment I used since this has been done according to the previous published work. Could you give any suggestions about correcting the input files? I would appreciate your kind help.

Best regards,

Yajun

I was trying to run the simulation using Test 23 files and got some problems.

I used the environmental condition used for model validation in https://www.nrel.gov/docs/fy10osti/45891.pdf (Denis's PhD thesis): 11 m/s hub-height wind speed, 10-m significant wave height and Tp of 17.64s. Based on the inital files, I made the following modifications:

In ElastoDyn, I disabled all the other DoFs except for the last six for the platform motion. RotSpeed was set to zero and BlPitch(i) were set to 90 in order to model the parked turbine state.

In HydroDyn, I changed WaveHs to 10 and WaveTp tp 17.64 and WaveDir to 0.

In AeroDyn, I raised the first aerodynamic node to 10m above the SWL and set WakeMod to zero.

In ServoDyn, I turned off the generator.

Besides, I extend the simulation time in fst file and HydroDyn file to 10800 s (3h) and increased Dt to 0.25.

I got the following error messeges:

FAST_Solution:CalcOutputs_And_SolveForInputs:SolveOption1:ED_HD_InputOutputSolve:HydroDyn_CalcOutp

ut: Angles in GetSmllRotAngs() are larger than 0.4 radians.

ED_HD_InputOutputSolve:HydroDyn_CalcOutput: Angles in GetSmllRotAngs() are larger than 0.4

radians.

FAST_Solution:CalcOutputs_And_SolveForInputs:SolveOption2:InflowWind_CalcOutput:CalcOutput:IfW_Uni

formWind_CalcOutput:GetWindSpeed:Height must not be negative.

IfW_UniformWind_CalcOutput: Error calculating the wind speed at position (-4.31086E+09,

2.42859E+09, -4.99252E+09) in the wind-file coordinates

CalcOutputs_And_SolveForInputs:SolveOption1:ED_HD_InputOutputSolve:HydroDyn_CalcOutput: Angles in

GetSmllRotAngs() are larger than 0.4 radians.

ED_HD_InputOutputSolve:HydroDyn_CalcOutput: Angles in GetSmllRotAngs() are larger than 0.4

radians.

FAST encountered an error at simulation time 7.75 of 10800 seconds.

Simulation error level: FATAL ERROR

Aborting FAST.

I think FAST is capable of simulating the model under the environment I used since this has been done according to the previous published work. Could you give any suggestions about correcting the input files? I would appreciate your kind help.

Best regards,

Yajun