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by Jason.Jonkman
Wed May 05, 2021 3:34 pm
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 362
Views: 76828

Re: FAST theory manual

Sent.
by Jason.Jonkman
Wed May 05, 2021 10:55 am
Forum: Computer-Aided Engineering Software Tools
Topic: Mlife - User Defined Distribution
Replies: 21
Views: 2985

Re: Mlife - User Defined Distribution

Dear Jian, I'm not sure why you want to simulate turbulence in FAST.Farm without wake meandering, but I agree that using the default spatial coherence parameters will result in unrealistically limited wake meandering. I'm not sure I understand your "factor of 43"; from what I can tell, you...
by Jason.Jonkman
Wed May 05, 2021 10:34 am
Forum: Computer-Aided Engineering Software Tools
Topic: VTK output to binary output
Replies: 7
Views: 1318

Re: VTK output to binary output

Dear Juan, I'm not sure I fully understand your question or what you are trying to do. I agree that the ED_TowerPtLoads forces and moments are the loads applied to ElastoDyn tower model as output from other modules. AeroDyn can apply aerodynamic loads on the tower, as can tower-based TMDs (from Serv...
by Jason.Jonkman
Wed May 05, 2021 10:14 am
Forum: Computer-Aided Engineering Software Tools
Topic: Mlife - User Defined Distribution
Replies: 21
Views: 2985

Re: Mlife - User Defined Distribution

Dear Jian, Your TurbSim inputs look reasonable to me. Presumably you've also set the reasonable spatial coherence parameters, as discussed in section 5.2.3 of the FAST.Farm User's Guide and Theory Manual: https://www.nrel.gov/docs/fy21osti/78485.pdf. I'm not really sure why the tower fatigue lifetim...
by Jason.Jonkman
Wed May 05, 2021 8:57 am
Forum: Computer-Aided Engineering Software Tools
Topic: Mlife - User Defined Distribution
Replies: 21
Views: 2985

Re: Mlife - User Defined Distribution

Dear Jian, Overall your process looks correct to me. One detail you missed was the tower thickness scaling factor of 1.3, so the tower-base thickness should actually be 0.027*1.3 = 0.0351 m, which will increase LUlt of the tower-base to 458319 kNm. What does that do to the tower design life? Best re...
by Jason.Jonkman
Wed May 05, 2021 7:58 am
Forum: Computer-Aided Engineering Software Tools
Topic: Natural frequency DeepCWind and Random Seeds
Replies: 11
Views: 370

Re: Natural frequency DeepCWind and Random Seeds

Dear Andre, Interpretation of the eigensolution has been discussed many times on this forum, including a discussion of the scripts from the MATLAB Toolbox (https://github.com/OpenFAST/matlab-toolbox)--such as MBC3 and runCampbell--that can aid in the interpretation of the MATLAB eig() function. The ...
by Jason.Jonkman
Wed May 05, 2021 7:09 am
Forum: Computer-Aided Engineering Software Tools
Topic: Extreme events
Replies: 30
Views: 14540

Re: Extreme events

Dear Abhinay, The steady extreme wind model does not involve transients. The standard says a constant yaw misalignment of +/-15deg is to be used. Load cases with the steady extreme wind model are meant be simulated via quasi-steady analysis, rather than via dynamic time-domain simulations. Best rega...
by Jason.Jonkman
Wed May 05, 2021 6:42 am
Forum: Testing
Topic: OpenFast Regression tests
Replies: 24
Views: 15201

Re: OpenFast Regression tests

Dear Sebastian, I agree that the oscillations appear to be coming from the controller. I would guess the 13-s period (0.077 Hz frequency) is coming from the PI-based blade-pitch controller. Did you change this OpenFAST model (of the NREL 5-MW baseline wind turbine with blades modeled in BeamDyn) in ...
by Jason.Jonkman
Mon May 03, 2021 9:16 am
Forum: Testing
Topic: OpenFast Regression tests
Replies: 24
Views: 15201

Re: OpenFast Regression tests

Dear Sebastian, It looks like this model has not yet reached equilibrium and you are seeing the start-up transient. The oscillations in blade pitch are commensurate with the oscillations in rotor speed. The system is not in equilibrium because the blades and tower are initialized in the undeflected ...
by Jason.Jonkman
Mon May 03, 2021 7:11 am
Forum: Controls
Topic: A question concerning Cp surface generation with OpenFAST
Replies: 22
Views: 401

Re: A question concerning Cp surface generation with OpenFAST

Dear Bartosz, I'm not sure I fully understand what you are doing. As far as I could tell, you are assessing the steady-state response at 3, 11.4, 13, and 15.5 m/s by running one long simulation with slow wind-speed ramps in between. I'm not sure what you are plotting in the Torque Regions.png images...
by Jason.Jonkman
Mon May 03, 2021 6:47 am
Forum: Computer-Aided Engineering Software Tools
Topic: Running OC4 DeepCWind for wind only
Replies: 6
Views: 107

Re: Running OC4 DeepCWind for wind only

Dear Andre, A parked or idling rotor is typically modeled with the blade leading edge facing the wind (to reduce aerodynamic loads), typically using BlPitch = 90deg (or so); pitch angles typically don't exceed this maximum value. A wind turbine operating below rated typically has blades pitched to f...
by Jason.Jonkman
Mon May 03, 2021 6:42 am
Forum: Computer-Aided Engineering Software Tools
Topic: Changing water depth for DeepCwind Model etc.
Replies: 20
Views: 466

Re: Changing water depth for DeepCwind Model etc.

Dear Andre,

Free-decay simulations of floating offshore wind turbines are typically run without incident waves. This means HydroDyn is enabled and WaveMod = 0, in which case the WaveSeed(s) are not used by HydroDyn.

Best regards,
by Jason.Jonkman
Mon May 03, 2021 6:40 am
Forum: Computer-Aided Engineering Software Tools
Topic: Question about Turbsim
Replies: 5
Views: 163

Re: Question about Turbsim

Dear Mazi, The last version of TurbSim before our NWTC Information Portal crashed (TurbSim v2.00.07a-bjj) is available on my Google drive: https://drive.google.com/file/d/1eCvgoOnvJrxsMgXxewDQFBQ5w3k3l_WB/view?usp=sharing. Even newer versions of TurbSim are available in the OpenFAST repository on gi...
by Jason.Jonkman
Mon May 03, 2021 6:35 am
Forum: Computer-Aided Engineering Software Tools
Topic: Visualize full-field Turbsim data and anemometer equivalent wind speed
Replies: 23
Views: 4251

Re: Visualize full-field Turbsim data and anemometer equivalent wind speed

Dear Manolis, The *.f90 file is the source code; you must compile this version of TurbSim before running a simulation. The compiled version should have a *.exe extension on Windows. You can find an archive of TurbSim v2.00.07a-bjj on my Google drive that contains the TurbSim source code, documentati...
by Jason.Jonkman
Mon May 03, 2021 6:28 am
Forum: Structural Analysis
Topic: Fatigue analysis
Replies: 5
Views: 4187

Re: Fatigue analysis

Dear Satwik,

I just sent you an e-mail.

Best regards,

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