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by Jason.Jonkman
Tue Jun 15, 2021 11:39 am
Forum: Computer-Aided Engineering Software Tools
Topic: Error during linearization with VolturnUS-S
Replies: 6
Views: 42

Re: Error during linearization with VolturnUS-S

Dear Andre, The values you have obtained through the OpenFAST linearization are quite close to those reported. I'm not really familiar enough with the Volturn-US model or report to know how the reported values were obtained. Of course, you could check that the OpenFAST linearization results are conv...
by Jason.Jonkman
Tue Jun 15, 2021 11:25 am
Forum: Rotor Aerodynamics
Topic: two mass model
Replies: 1
Views: 7

Re: two mass model

Dear Cameron,

Are you asking what value ElastoDyn calculates for the rotor inertia? This is written to the ElastoDyn summary file, *.ED.sum, which is written when OpenFAST is run with SumPrint = True set in ElastoDyn.

Best regards,
by Jason.Jonkman
Tue Jun 15, 2021 11:22 am
Forum: NWTC Wind Data
Topic: Offshore Wind Data
Replies: 14
Views: 11417

Re: Offshore Wind Data

Dear Salem,

The previous website (the NWTC Information Portal) where that spreadsheet was stored has been taken down. You can now find that spreadsheet on my Google drive: https://drive.google.com/file/d/1zeiYQo ... sp=sharing.

Best regards,
by Jason.Jonkman
Mon Jun 14, 2021 4:51 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Hydrodynamic coefficients HELP!
Replies: 30
Views: 1253

Re: Hydrodynamic coefficients HELP!

Dear Bartsoz, The off-diagonal terms come from the fact that the mooring line fairleads are not placed at (0,0,0). So, the force caused by translation will result in moment; likewise rotation will cause a force. The sign is based on the coordinate system with surge-pitch coupling the opposite sign (...
by Jason.Jonkman
Mon Jun 14, 2021 3:42 pm
Forum: Computer-Aided Engineering Software Tools
Topic: ServoDyn error
Replies: 1
Views: 28

Re: ServoDyn error

Dear Bruce, Not all precompiled binary executables of OpenFAST require the Intel redistributable libraries; the ones that do were built to require dynamic libraries from Intel rather than being compiled with Intel static libraries. I don't recall what OpenFAST v1.0.0 requires, but regardless, I woul...
by Jason.Jonkman
Mon Jun 14, 2021 3:30 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Direct drive generator and edgewise bending of the blades
Replies: 4
Views: 54

Re: Direct drive generator and edgewise bending of the blades

Dear Bartosz, I agree with your interpretation of the drivetrain DOF in the ElastoDyn module of FAST / OpenFAST. And I agree that for direct-drive wind turbines, with a short, stiff shaft, that the drivetrain DOF can be disabled. I'm not sure which baseline controller you are referring to, but a low...
by Jason.Jonkman
Mon Jun 14, 2021 3:17 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Two-blades wind turbine
Replies: 5
Views: 91

Re: Two-blades wind turbine

Dear Tianhui.Liu, I'm not sure I know the history all models in the OpenFAST r-test are set up the way the are, but they are more set up as examples that can be used to test the various functionality of OpenFAST. Regarding AWT_YFree_WTurb, this model is set up with GenDOF = False and RotSpeed = 53.3...
by Jason.Jonkman
Fri Jun 11, 2021 10:55 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 375
Views: 82838

Re: FAST theory manual

Sent.
by Jason.Jonkman
Fri Jun 11, 2021 10:34 am
Forum: Computer-Aided Engineering Software Tools
Topic: Inhomogen turbulent windfield
Replies: 11
Views: 2789

Re: Inhomogen turbulent windfield

Dear Jian,

The Intel command prompt can be opened by clicking on the associated link from the Start menu:
IntelCommandPrompt_StartMenu.png
IntelCommandPrompt_StartMenu.png (75.94 KiB) Viewed 40 times

When opened, the Intel command prompt looks like this:
IntelCommandPrompt.png
IntelCommandPrompt.png (14.82 KiB) Viewed 40 times

Best regards,
by Jason.Jonkman
Fri Jun 11, 2021 10:28 am
Forum: Inflow Turbulence
Topic: Turbsim for Class IV from IEC 61400-1 2nd edition
Replies: 9
Views: 3875

Re: Turbsim for Class IV from IEC 61400-1 2nd edition

Dear Jian, My answers to questions 1-3 are yes. Regarding (1), I would say that the IEC 61400-3 does not recommend that the equation sigma_1=V_hub/ln(Z_hub/Z_0)+1.28*1.44*I_15 be used to define the design turbulence level; instead, the equations from IEC 61400-1 define that (same for land and offsho...
by Jason.Jonkman
Fri Jun 11, 2021 10:24 am
Forum: Computer-Aided Engineering Software Tools
Topic: Aerodyn standalone version
Replies: 8
Views: 93

Re: Aerodyn standalone version

Dear Florence, Downloading OpenFAST from https://github.com/OpenFAST/openfast should give you OpenFAST v2.6 as of now, assuming that you've selected the main branch. The AeroDyn input file available from readthedocs (https://openfast.readthedocs.io/en/main/_downloads/1270204a8cbfec62f2a41a8d746a9ce6...
by Jason.Jonkman
Fri Jun 11, 2021 9:04 am
Forum: Computer-Aided Engineering Software Tools
Topic: Error during linearization with VolturnUS-S
Replies: 6
Views: 42

Re: Error during linearization with VolturnUS-S

Dear Andre, The "nodal output" warning will not effect the simulation results; you can ignore the warning. Otherwise, the error messages are pointing to the solution: ⋅ Set WvDiffQTF = False -- You cannot linearize HydroDyn with 2nd-order wave kinematics enabled ⋅ Set D...
by Jason.Jonkman
Fri Jun 11, 2021 8:10 am
Forum: Computer-Aided Engineering Software Tools
Topic: Gain Scheduling
Replies: 27
Views: 13541

Re: Gain Scheduling

Dear Adèle, When the rotor is spinning, I would not recommend using NLinTimes = 1. When the rotor is spinning, I would generally recommend linearizing every 10-degrees of azimuth, so, NLinTimes, which is the number of times to linearize in one rotor revolution should be set to 36. NLinTimes = 1 is m...
by Jason.Jonkman
Thu Jun 10, 2021 5:52 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Aerodyn standalone version
Replies: 8
Views: 93

Re: Aerodyn standalone version

Dear Florence, Your error is pointing to a problem with your input file format. Even if you are not modeling an MHK rotor, you still must have the CavitCheck, Patm, Pvap, and FluidDepth inputs in your AeroDyn input file associated with OpenFAST v2.1, which looks to be the version you are running. As...
by Jason.Jonkman
Thu Jun 10, 2021 1:38 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Modelling Tower
Replies: 12
Views: 1270

Re: Modelling Tower

I've now raised the inability of OpenFAST v2.6 to visualize offshore support structures in the following OpenFAST github issue: https://github.com/OpenFAST/openfast/issues/776.

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