Error calculating the wind speed at position

Mustafa.Vardaroglu · February 11, 2019, 3:16pm

Dear All,

I am trying to see the response of the MIT/NREL TLP under steady wind conditions.
I am simply executing Test23.fst file with only setting Windtype=1 from InflowWind INPUT FILE.
Execution is aborted with the message below. I did not change anything in source codes except the WindType.
I am attaching the .out file. According to the .out file, execution is aborted at the first time step.
I am requesting the wind speed only at one point, at hub height (WindVxiList=0,WindVyiList=0,WindVziList=90)
The error message consists of: “Error calculating the wind speed at position (-5.64793E-05,-1.90721E-06, -1.11292E-05) in the wind-file coordinates”
I see that the error is related to coordinate system. I am checking FAST 7.0 Manual for coordinate system definition. But can not find anyting.

Do you have any idea?

Sincerely,
Mustafa

cmdout=

FAST (v8.16.00a-bjj, 27-Jul-2016)

This program comes with ABSOLUTELY NO WARRANTY. See the “license.txt” file distributed with this
software for details.

Running FAST (v8.16.00a-bjj, 27-Jul-2016), compiled as a 64-bit application using single
precision
linked with NWTC Subroutine Library (v2.09.00, 23-Jul-2016)

Heading of the FAST input file:
FAST Certification Test #23: NREL 5.0 MW Baseline Wind Turbine with MIT-NREL TLP
Configuration, for use in offshore analysis

Running ElastoDyn (v1.04.00a-bjj, 26-Jul-2016).

Running AeroDyn (v15.03.00, 27-Jul-2016).

Running AirfoilInfo (v1.01.00a-bjj, 5-Apr-2016).

Running BEM (v1.02.00, 29-Jun-2016).
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 1, Blade = 1
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 2, Blade = 1
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 3, Blade = 1
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 4, Blade = 1
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 1, Blade = 2
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 2, Blade = 2
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 3, Blade = 2
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 4, Blade = 2
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 1, Blade = 3
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 2, Blade = 3
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 3, Blade = 3
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 4, Blade = 3

Running InflowWind (v3.03.00, 26-Jul-2016).
Opening InflowWind input file: .\5MW_Baseline/NRELOffshrBsline5MW_InflowWind_12mps.dat

Running ServoDyn (v1.06.00a-bjj, 26-Jul-2016).

Running ServoDyn Interface for Bladed Controllers (using Intel Visual Fortran for Windows,
14-Oct-2015).

Running HydroDyn (v2.05.01, 27-Jul-2016).
Generating incident wave kinematics and current time history.
Reading in WAMIT output with root name “.\5MW_Baseline/HydroData/tlpmit”.
Computing radiation impulse response functions and wave diffraction forces.

Running FEAMooring (v1.02.01, 23-Jul-2016).
Heading of the FEAMooring input file: NREL 5.0 MW offshore baseline floating platform input
properties for the MIT/NREL TLP. #rho=1025; WtrDpth=200
Number of iterations without Seabed :18
Number of final iterations :46

FAST_InitializeAll:InflowWind_Init:InflowWind_SetParameters:SetOutParam:-- is not an available
output channel.
FAST_InitializeAll:HydroDyn_Init:Waves_Init:VariousWaves_Init:Changed WaveNDir from 13 to 15 so
that an equal number of frequencies are assigned to each direction.

Timestep: 0 of 60 seconds.

FAST_Solution0:CalcOutputs_And_SolveForInputs:SolveOption2:SrvD_CalcOutput:Running with torque
and pitch control of the NREL offshore 5MW baseline wind turbine from DISCON.dll as written by J.
Jonkman of NREL/NWTC for use in the IEA Annex XXIII OC3 studies.

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 (-5.64793E-05,
-1.90721E-06, -1.11292E-05) in the wind-file coordinates

FAST encountered an error at simulation time 0 of 60 seconds.
Simulation error level: FATAL ERROR

Aborting FAST.
Test23out.txt (4.01 KB)

Jason.Jonkman · February 11, 2019, 4:56pm

Dear Mustafa,

Test23 uses an AeroDyn v15 input file with tower aerodynamic loads enabled and the first tower aerodynamic node is located at the tower base (at (0,0,0) in the inertial-frame coordinate system). In the floating system, if the tower heaves downward a bit, this means that the first tower aerodynamic node will pass below the still water level, which FAST is complaining about. I suggest increasing the elevation of the first tower aerodynamic node a little bit to keep the node from passing below the still water level.

Best regards,

Sai.Chaitanya · February 16, 2019, 6:00am

Dear Mustafa,

I am so thankful for your reply. I have tried increasing the tower elevation other than 10m and yet the problem is persisting.

FAST_Solution0:CalcOutputs_And_SolveForInputs:SolveOption2:SrvD_CalcOutput:Running with torque
and pitch control of the NREL offshore 5MW baseline wind turbine from DISCON.dll as written by J.
Jonkman of NREL/NWTC for use in the IEA Annex XXIII OC3 studies. Includes modifications for the
Hywind spar.
Timestep: 17 of 3600 seconds. Estimated final completion at 12:18:60.

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 (-0.83295, -28.578,
-0.4041) in the wind-file coordinates

FAST encountered an error at simulation time 17.613 of 3600 seconds.
Simulation error level: FATAL ERROR

Aborting FAST.

I will be glad if you could help me with this.

Thank you.