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by Jason.Jonkman
Tue Oct 27, 2020 6:53 am
Forum: General
Topic: FAST.Farm
Replies: 87
Views: 12323

Re: FAST.Farm

Dear Jiaping, I don't have access to your Google drive folder; I've submitted a request for access. Two wake planes are separated by the wake propagation speed (which would be the spatially averaged mean wind speed minus a contribution from the wake deficit) times the low-resolution domain time step...
by Jason.Jonkman
Mon Oct 26, 2020 9:44 am
Forum: General
Topic: FAST.Farm
Replies: 87
Views: 12323

Re: FAST.Farm

Dear Jiaping, You haven't provided enough information for me to understand the cause of the large angle of attack warning. A few clarifying questions: ⋅ How soon into the simulation does this warning appear? ⋅ How is the turbine responding at the time of the warning? Are the roto...
by Jason.Jonkman
Mon Oct 26, 2020 7:30 am
Forum: General
Topic: FAST.Farm
Replies: 87
Views: 12323

Re: FAST.Farm

Dear Jiaping, Regarding 1.1, the position (515.32, 37.154, 124.56) is in the coordinate system of wind turbine #1, whose origin is at (5,0,0) in the FAST.Farm global coordinates. So, the global coordinates of this position are (520.32, 37.154, 124.56). However, the high-resolution box only extends t...
by Jason.Jonkman
Mon Oct 26, 2020 7:08 am
Forum: Computer-Aided Engineering Software Tools
Topic: Modelling Tower
Replies: 1
Views: 49

Re: Modelling Tower

Dear Malte, It sounds like you've specified the tower properly in ElastoDyn. The issue you've identified is a limitation of the surface visualization feature of OpenFAST. The surface visualization of the tower is based on the ElastoDyn inputs TowerHt and TowerBsHt, but because the tower diameter is ...
by Jason.Jonkman
Mon Oct 26, 2020 7:00 am
Forum: Rotor Aerodynamics
Topic: Use of AeroDyn Driver
Replies: 5
Views: 156

Re: Use of AeroDyn Driver

Dear Vishal, Typically the term "airfoil polars" refers to the lift and drag (and, perhaps, pitching-moment) data as a function of angle of attack; you always need these data in the airfoil data input file. But when InclUAdata = False, the 32 UA model parameters do not need to be specified...
by Jason.Jonkman
Mon Oct 26, 2020 6:55 am
Forum: General
Topic: openfast v2.3
Replies: 10
Views: 761

Re: openfast v2.3

Dear Akheel,

Setting CompInflow = 0 will set the wind speed to 0 throughout the domain (still air).

Best regards,
by Jason.Jonkman
Sat Oct 24, 2020 8:36 am
Forum: Computer-Aided Engineering Software Tools
Topic: Monopile loading spectra for OC3 - case 5.3
Replies: 21
Views: 6125

Re: Monopile loading spectra for OC3 - case 5.3

Dear Manuela, Is the problem the output sensor you are plotting? In the older FAST v7 tool, the monopile was modeled as an extension of the tower, such that the tower base load (TwrBsMyt) is at the mudline. In the newer OpenFAST tool that you are using, the tower is modeled in ElastoDyn and the mono...
by Jason.Jonkman
Sat Oct 24, 2020 8:27 am
Forum: Rotor Aerodynamics
Topic: Unsteady Aerodynamics Turning Off
Replies: 5
Views: 527

Re: Unsteady Aerodynamics Turning Off

Dear Ramya, I'm not sure I can answer your question generally. UACutOut is really there to ensure users do not apply the unsteady airfoil aerodynamics model beyond what the model is valid for. Do you have a sense of what the unsteady airfoil aerodynamic hysteresis loop (e.g., Cl versus AoA) should l...
by Jason.Jonkman
Sat Oct 24, 2020 8:18 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST theory manual
Replies: 346
Views: 58970

Re: FAST theory manual

Sent.
by Jason.Jonkman
Sat Oct 24, 2020 8:15 am
Forum: General
Topic: openfast v2.3
Replies: 10
Views: 761

Re: openfast v2.3

Dear Akheel, Here are my answers to your questions: 1. CompAero determines how aerodynamic applied loads on the structure are calculated (i.e., which version of AeroDyn is called, or to disable aerodynamic loads altogether) whereas CompInflow determines how ambient wind is defined (i.e., from Inflow...
by Jason.Jonkman
Thu Oct 22, 2020 8:32 am
Forum: Computer-Aided Engineering Software Tools
Topic: FAST v8
Replies: 4
Views: 691

Re: FAST v8

Dear Narender, As has been mentioned several times on this forum, the old wind.nrel.gov site is no longer available. While the new site is being developed, I've place the old archive of FAST v8.16 on my Google drive--see: https://drive.google.com/drive/folders/10Pw8zzOr_YqIgtLmq10XhYpdAveKAWAJ?usp=s...
by Jason.Jonkman
Thu Oct 22, 2020 8:09 am
Forum: General
Topic: FAST.Farm
Replies: 87
Views: 12323

Re: FAST.Farm

Dear Deza,

The Wind Energy journal publication I referred to above has now been posted online--see: https://onlinelibrary.wiley.com/doi/10.1002/we.2581.

Best regards,
by Jason.Jonkman
Wed Oct 21, 2020 6:51 am
Forum: Computer-Aided Engineering Software Tools
Topic: 15MW MaineSemi-sub floater simulation shows tower strike
Replies: 8
Views: 455

Re: 15MW MaineSemi-sub floater simulation shows tower strike

Dear Rui.Hao, I gather you are referring to the various output parameter names set in the OutLists of each module. These are described in the respective module-level documentation. The full set of OutList parameters are also documented in the OutListParameters.xlsx spreadsheet provided with OpenFAST...
by Jason.Jonkman
Wed Oct 21, 2020 6:47 am
Forum: Controls
Topic: model Validation
Replies: 27
Views: 3976

Re: model Validation

Dear Satish, The hydrodynamic analysis node locations are written to the HydroDyn summary file. You'd presumably need access to a software that can calculate wave kinematics (including stretching) at these locations. NREL has not provided such a software. The HydroDyn module of OpenFAST can output w...
by Jason.Jonkman
Wed Oct 21, 2020 6:36 am
Forum: General
Topic: FAST.Farm
Replies: 87
Views: 12323

Re: FAST.Farm

Dear Jiaping, The primary FAST.Farm input (*.fstf) file has not changed since the version of the precompiled Windows executable and the newer version on github, other than the addition of the Mod_AmbWind = 3 option. The Mod_AmbWind = 3 option does not change the formatting of the file (it does not a...

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