Search found 4223 matches

by Jason.Jonkman
Fri Sep 20, 2019 7:01 am
Forum: Airfoils
Topic: Making fault
Replies: 24
Views: 7834

Re: Making fault

Dear Sebastian, I'm not sure I'm understand enough about what you are doing to comment why you are not getting the result you expect in one case and why the OpenFAST crashes in another case. I did noticed from your earlier post that you call your new AddMass SUBROUTINE at n_t_global == 5. Please not...
by Jason.Jonkman
Tue Sep 17, 2019 9:39 am
Forum: Wind Farm Modeling
Topic: Special site classification
Replies: 3
Views: 55

Re: Special site classification

Dear Masoud, Here are my answers to your questions: 1) The IEC design standards do not directly consider seasonable variability when defining the wind turbine class. Instead, the IEC standard relies, e.g., on the annual average wind speed (Vave) and the extreme wind speeds based on the 50 and 1 year...
by Jason.Jonkman
Tue Sep 17, 2019 8:57 am
Forum: Computer-Aided Engineering Software Tools
Topic: Problem reading binary output file
Replies: 3
Views: 18

Re: Problem reading binary output file

Dear Rubén,

I'm glad that solved the problem. I've now raised this issue on OpenFAST: https://github.com/OpenFAST/openfast/issues/331.

Best regards,
by Jason.Jonkman
Tue Sep 17, 2019 6:40 am
Forum: Computer-Aided Engineering Software Tools
Topic: Problem reading binary output file
Replies: 3
Views: 18

Re: Problem reading binary output file

Dear Ruben, Are you outputting the binary file with OutFileFmt=2? The readFASTbinary script provided in the MATLAB Toolbox should be able to read this file type without problem. In OpenFAST, a different binary file type is available by specifying OutFileFmt=0. This is really an undocumented feature ...
by Jason.Jonkman
Tue Sep 17, 2019 6:33 am
Forum: Computer-Aided Engineering Software Tools
Topic: fore-aft and side-to-side accelerations at mid-tower
Replies: 7
Views: 1263

Re: fore-aft and side-to-side accelerations at mid-tower

Dear Mustafa,

Yes, you can use ElastoDyn outputs TwHt*TDxt, TwHt*TDyt, and TwHt*TDzt to get the xt, yt, and zt displacements, respectively, at up to 9 output nodes along the tower, where * is between 1 and 9.

Best regards,
by Jason.Jonkman
Tue Sep 17, 2019 6:29 am
Forum: Computer-Aided Engineering Software Tools
Topic: Natural Frequencies with FAST v8
Replies: 7
Views: 9667

Re: Natural Frequencies with FAST v8

Dear Mustafa,

Instead of providing a unit impulse, you can set an initial tower-top displacement (in the ElastoDyn module) to conduct a free-decay test of the tower oscillation.

Best regards,
by Jason.Jonkman
Mon Sep 16, 2019 6:17 am
Forum: Computer-Aided Engineering Software Tools
Topic: GRCGEARSCouP
Replies: 1
Views: 12

Re: GRCGEARSCouP

Dear Aurea, I've never used Gear-SCouP myself, but its website (https://nwtc.nrel.gov/software/caetools/simulators/gear-scoup) says: You will need the MATLAB Compiler Runtime executable version 7.16 for Windows 64-bit which can be found here ( https://nwtc.nrel.gov/MatLab_MCRInstaller ). Best regards,
by Jason.Jonkman
Thu Sep 12, 2019 9:07 am
Forum: Computer-Aided Engineering Software Tools
Topic: MIT/NREL TLP
Replies: 8
Views: 6064

Re: MIT/NREL TLP

Dear Mustafa,

The tower-base boundary condition has a large influence on the tower natural frequency. The land-based turbine has a fixed / cantilevered boundary condition. The TLP has 6 degree-of-freedom motion with mass / inertia and stiffness.

Best regards,
by Jason.Jonkman
Thu Sep 12, 2019 9:04 am
Forum: Computer-Aided Engineering Software Tools
Topic: RunIEC accessibility
Replies: 10
Views: 3013

Re: RunIEC accessibility

Sent.
by Jason.Jonkman
Wed Sep 11, 2019 12:11 pm
Forum: General
Topic: Changing wave direction
Replies: 3
Views: 23

Re: Changing wave direction

Dear Krishnaveni,

I'm not sure what you mean by "rotate the spar", but you can introduce platform rotation via the structural degrees of freedom in ElastoDyn. However, ElastoDyn limits the platform rotations to small angles (so, you can't set them to 90 degrees).

Best regards,
by Jason.Jonkman
Wed Sep 11, 2019 10:56 am
Forum: General
Topic: Changing wave direction
Replies: 3
Views: 23

Re: Changing wave direction

Dear Krishnaveni, Correct, the location on the platform where the waves hit does not change with the wave direction (WaveDir) in HydroDyn. However, WaveDir will impact the direction of the hydrodynamic loads, e.g., for an axisymmetric structure the hydrodynamic loads will act in the surge and pitch ...
by Jason.Jonkman
Wed Sep 11, 2019 10:51 am
Forum: Rotor Aerodynamics
Topic: Turbine shut down operation
Replies: 5
Views: 68

Re: Turbine shut down operation

Yes, those look like reasonable settings to me.

Best regards,
by Jason.Jonkman
Wed Sep 11, 2019 8:41 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 222
Views: 29313

Re: FAST theory manual

Sent.
by Jason.Jonkman
Wed Sep 11, 2019 6:57 am
Forum: Computer-Aided Engineering Software Tools
Topic: Disable torque data in FAST
Replies: 1
Views: 28

Re: Disable torque data in FAST

Dear Mikael, Disabling the generator degree of freedom (GenDOF) will force the generator to spin at a constant speed regardless of the torques applied. Disabling the drivetrain-torsion DOF (DrTrDOF) will also eliminate the torsional flexibility of the shaft (so if both GenDOF and DrTrDOF = False, th...
by Jason.Jonkman
Tue Sep 10, 2019 6:44 am
Forum: Computer-Aided Engineering Software Tools
Topic: Blade Tip-brake Model in OpenFAST
Replies: 2
Views: 26

Re: Blade Tip-brake Model in OpenFAST

Dear Moe Moe, NREL has still not been funded to implement a tip brake into FAST v8 or OpenFAST. I'll let others on the forum comment if they've developed something. The tip-brake model of FAST v7 and older was a very simple model that could likely be tailored to model the braking of any type of tip-...

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