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by Jason.Jonkman
Fri Feb 22, 2019 11:56 am
Forum: Computer-Aided Engineering Software Tools
Topic: Routine to extract data from FAST output files
Replies: 1
Views: 3

Re: Routine to extract data from FAST output files

Dear Arturo, The NREL provided MATLAB toolbox (https://github.com/OpenFAST/matlab-toolbox) has generally functionality for reading in data from FAST output files for plotting and other post-processing. Also, the MATLAB-based post-processors MCrunch, MLife, and MExtremes support wind-turbine specific...
by Jason.Jonkman
Fri Feb 22, 2019 6:46 am
Forum: Controls
Topic: Coefficients of 5MW WT
Replies: 11
Views: 83

Re: Coefficients of 5MW WT

Dear Sina,

The structural stiffness and damping related to the drivetrain torsion are linear (and so, are independent of the operating point), but the aerodynamic stiffness and damping are likely dependent on the operating point.

Best regards,
by Jason.Jonkman
Thu Feb 21, 2019 3:20 pm
Forum: Computer-Aided Engineering Software Tools
Topic: BeamDyn Coordinate Systems in OpenFAST
Replies: 13
Views: 78

Re: BeamDyn Coordinate Systems in OpenFAST

Hi Ryan, I'm not sure, as I would not expect the loads to differ between the root and the first node. I've placed this potential bug in BeamDyn (as well as the documentation bug) as an issue on the OpenFAST github site: https://github.com/OpenFAST/openfast/issues/248. I suggest discussing this poten...
by Jason.Jonkman
Thu Feb 21, 2019 3:00 pm
Forum: Controls
Topic: Coefficients of 5MW WT
Replies: 11
Views: 83

Re: Coefficients of 5MW WT

Dear Sina, I'm not sure I understand your first question, but FAST and Test18 do include the drivetrain-torsion degree of freedom (DOF). The generator speed is proportional to the low-speed shaft speed at the entrance to the gearbox (via the gearbox ratio), but there is a torsional DOF (with spring-...
by Jason.Jonkman
Thu Feb 21, 2019 8:58 am
Forum: Controls
Topic: Linear model DTU 10MW Triple spar
Replies: 1
Views: 9

Re: Linear model DTU 10MW Triple spar

Dear Jan, If your only issue is that your model uses AeroDyn v14, but the linearization functionality is only available in AeroDyn v15, I would simply upgrade your AeroDyn v14 model to v15. Please note that we have recently added linearization functionality in OpenFAST for floating offshore wind tur...
by Jason.Jonkman
Thu Feb 21, 2019 8:39 am
Forum: Computer-Aided Engineering Software Tools
Topic: HydroDyn - example .1, .3 and .hst files
Replies: 3
Views: 28

Re: HydroDyn - example .1, .3 and .hst files

Dear Jack, You can't eliminate the blades, drivetrain, nacelle, and tower from an OpenFAST model, but you can set the inputs so that terms associated with the blades, drivetrain, naccelle, and tower are zero or negligible. For example, you should disable wind inflow, aerodynamics, and control; disab...
by Jason.Jonkman
Wed Feb 20, 2019 2:39 pm
Forum: Computer-Aided Engineering Software Tools
Topic: MIT/NREL TLP without wind
Replies: 6
Views: 50

Re: MIT/NREL TLP without wind

Dear Mustafa, Regarding WaveDirMod, it looks like there is a small bug in HydroDyn. I've just reported this issue in OpenFAST: https://github.com/OpenFAST/openfast/issues/246. I'm not sure I understand your question regarding running FAST in MATLAB. I would not expect to see a "huge amount of r...
by Jason.Jonkman
Wed Feb 20, 2019 7:16 am
Forum: Computer-Aided Engineering Software Tools
Topic: MIT/NREL TLP without wind
Replies: 6
Views: 50

Re: MIT/NREL TLP without wind

Dear Mustafa, Have you applied low- or high-frequency cut-offs (WvLowCOff, WvHiCOff) that would zero out the wave spectrum at the regular wave frequency you are simulating? Test23 originally applied directional spreading (WaveDirMod=1) to the irregular sea state (WaveMod=2); have you tried disabling...
by Jason.Jonkman
Tue Feb 19, 2019 8:51 pm
Forum: Computer-Aided Engineering Software Tools
Topic: BeamDyn Coordinate Systems in OpenFAST
Replies: 13
Views: 78

Re: BeamDyn Coordinate Systems in OpenFAST

Dear Ryan, The 1st node in BeamDyn is indeed at the blade root, so, I would generally expect equivalent results between the root and 1st node (after twist rotations). My understanding is that the root and nodal reaction loads are calculated in a different way in BeamDyn, but that the results should ...
by Jason.Jonkman
Mon Feb 18, 2019 5:05 pm
Forum: Controls
Topic: HSS brake implementation within a DLL
Replies: 1
Views: 11

Re: HSS brake implementation within a DLL

Dear Quentin,

Here are my answers to your questions:

1) Bladed requires that avrSWAP(36) be set to 0 or 1. We've implemented the same requirement in the ServoDyn interface to the Bladed-style DLL controller.

2) Yes, that is certainly possible.

Best regards,
by Jason.Jonkman
Mon Feb 18, 2019 4:57 pm
Forum: Computer-Aided Engineering Software Tools
Topic: User defined spectrum from routine UserWaveSpctrm in HydroDYn
Replies: 4
Views: 26

Re: User defined spectrum from routine UserWaveSpctrm in HydroDYn

Dear Danupon,

The sample UserWaveSpctrm routine is included in the Waves.f90 source file of HydroDyn. The Omega and WaveDir arguments of the routine are the inputs.

Best regards,
by Jason.Jonkman
Mon Feb 18, 2019 6:42 am
Forum: Computer-Aided Engineering Software Tools
Topic: User defined spectrum from routine UserWaveSpctrm in HydroDYn
Replies: 4
Views: 26

Re: User defined spectrum from routine UserWaveSpctrm in HydroDYn

Dear Danupon, Hopefully the UserWaveSpctrm routine in HydroDyn is self-explanatory. This routine is called once per frequency at model initialization and receives the frequency (in rad/s) and direction (in degrees) of the wave component as input and returns the one-sided power-spectral density (PSD)...
by Jason.Jonkman
Sun Feb 17, 2019 4:48 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Directional Wave Spreading
Replies: 2
Views: 32

Re: Directional Wave Spreading

Dear Danupon, In the HydroDyn hydrodynamics module of FAST / OpenFAST, the wave directional spreading is not frequency dependent. We wrote a paper for OMAE 2014 when we first introduced wave directional spreading in HydroDyn; please review this paper for more information on the approach implemented:...
by Jason.Jonkman
Fri Feb 15, 2019 9:15 pm
Forum: Computer-Aided Engineering Software Tools
Topic: BeamDyn Coordinate Systems in OpenFAST
Replies: 13
Views: 78

Re: BeamDyn Coordinate Systems in OpenFAST

Dear Ryan, Have you changed the BeamDyn source code in some way? In NREL's version of BeamDyn, NNodeOuts can be at most 9, but you've set it to 42. (?) I would expect at the root, where the blade is cantilevered to the hub, that the only difference between the local (l) and root (r) coordinate syste...
by Jason.Jonkman
Fri Feb 15, 2019 10:30 am
Forum: Computer-Aided Engineering Software Tools
Topic: BeamDyn Coordinate Systems in OpenFAST
Replies: 13
Views: 78

Re: BeamDyn Coordinate Systems in OpenFAST

Dear Ryan,

What type of quadrature are you using? (1: Gauss; 2: Trapezoidal)

What do you have OutNd set to in your BeamDyn primary input file?

Best regards,

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