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by Jason.Jonkman
Mon May 10, 2021 9:40 am
Forum: Computer-Aided Engineering Software Tools
Topic: Extreme events
Replies: 35
Views: 14705

Re: Extreme events

Dear Vishal, It sounds like your controller is going unstable when you enable pitch control together with the pitch runaway event. Is this a controller NREL has provided or one you implemented yourself? Sounds like you may want to debug why the controller is going unstable. Typically a pitch runaway...
by Jason.Jonkman
Mon May 10, 2021 9:30 am
Forum: Rotor Aerodynamics
Topic: Printing the axial induction factor in FAST
Replies: 37
Views: 13606

Re: Printing the axial induction factor in FAST

Dear Ricardo,

I'm sorry, but I'm not sure I understand your question; please clarify.

Best regards,
by Jason.Jonkman
Mon May 10, 2021 9:26 am
Forum: Airfoils
Topic: Inlet Velocity for DU 35 and DU 40 Airfoils
Replies: 7
Views: 91

Re: Inlet Velocity for DU 35 and DU 40 Airfoils

Dear Victor, Are you asking why your CFD solution is not matching the airfoil data provided by NREL for the DU35 and DU40 airfoils? I'm not sure I can really answer that question, but your CFD solution likely depends on the solution method (2D or 3D CFD). discretization, and sub-grid scale turbulenc...
by Jason.Jonkman
Fri May 07, 2021 10:08 am
Forum: Computer-Aided Engineering Software Tools
Topic: VTK output to binary output
Replies: 16
Views: 1470

Re: VTK output to binary output

Dear Juan, Yes, the different magnitudes are from different units (AD: N/m; ED: N). Wind is applied already at t = 0s. The full set of blade node outputs from ElastoDyn is not part of the visualization functionality; instead, it is similar to the OutList functionality. It simply allows the user to b...
by Jason.Jonkman
Fri May 07, 2021 6:43 am
Forum: Computer-Aided Engineering Software Tools
Topic: Extreme events
Replies: 35
Views: 14705

Re: Extreme events

Dear Vishal, Your simulation settings seem OK, except that I would expect that you'd enable the pitch controller at the start of the simulation (TPCOn = 0.0 s). What wind speed are you receiving the high blade-root flap moment? Otherwise, I'm not sure I can comment on the results you are seeing with...
by Jason.Jonkman
Fri May 07, 2021 6:36 am
Forum: General
Topic: FAST.Farm
Replies: 205
Views: 25156

Re: FAST.Farm

Thanks, Younes, for your response to Jundong's question, which I agree with. Just one point of clarification: we often use the extension "fst" for the OpenFAST primary input file and "fstf" for the FAST.Farm primary input file, but the software do not require these extensions. Be...
by Jason.Jonkman
Fri May 07, 2021 6:32 am
Forum: Computer-Aided Engineering Software Tools
Topic: Natural frequency DeepCWind and Random Seeds
Replies: 22
Views: 530

Re: Natural frequency DeepCWind and Random Seeds

Dear Andre, By TowerLen and BladeLen, I assume you are referring to the inputs in the campbell_diagram_data.m script. These should be the length of the tower and blade that are modeled flexibly in your ElastoDyn model (i.e., BladeLen = TipRad - HubRad and TowerLen = TowerHt - TowerBsHt). However, th...
by Jason.Jonkman
Fri May 07, 2021 6:21 am
Forum: Airfoils
Topic: Inlet Velocity for DU 35 and DU 40 Airfoils
Replies: 7
Views: 91

Re: Inlet Velocity for DU 35 and DU 40 Airfoils

Dear Victor, Actually, you never mentioned what chordlength you are using in your original post. In the Re calculation, you should use the chordlength for L. You mentioned 3 m in your original post, but that is in the context of extrusion length, which I assumed you meant as the chordlength. If the ...
by Jason.Jonkman
Thu May 06, 2021 1:14 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Current definition problem
Replies: 1
Views: 54

Re: Current definition problem

Dear Bartosz, Regarding the current direction, HydroDyn uses the same convention as for waves: 0deg current flows along the X-axis and 90eg current flows along the Y-axis. In your case, where X = North, East = -Y, so, you'd have to specify a current direction of -90deg to flow East (along -Y). Other...
by Jason.Jonkman
Thu May 06, 2021 1:04 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Linearization OC4Semi OpenFAST : unable to find steady-state solution
Replies: 2
Views: 50

Re: Linearization OC4Semi OpenFAST : unable to find steady-state solution

Dear Salic, From my brief look at your input files, I see that you've disabled wave radiation altogether in HydroDyn (RdtnMod = 0). So, your state-space model is not being used. Regarding convergence, your simulation is only 100-s long (TMax = 100), which is not long given the low natural frequency ...
by Jason.Jonkman
Thu May 06, 2021 12:53 pm
Forum: Computer-Aided Engineering Software Tools
Topic: VTK output to binary output
Replies: 16
Views: 1470

Re: VTK output to binary output

Dear Juan, There difference between the aerodynamic loads output from AeroDyn (AD_Tower) and and the aerodynamic loads input to ElastoDyn (ED_TowerPtLoads) are: ⋅ The AeroDyn output is a Line2 mesh with loads per unit length (e.g., N/m for force at a node) while the ElastoDyn input is a Po...
by Jason.Jonkman
Thu May 06, 2021 12:06 pm
Forum: Inflow Turbulence
Topic: TURBSIM wind field discontinuity
Replies: 9
Views: 264

Re: TURBSIM wind field discontinuity

Dear Mustafa, I agree, that the "DEFAULT" option is no spatial coherence in the v- and w-components; this is because default values are not specified in the IEC design standards. But to obtain spatial coherence of the v- and w-components, you can set SCMod2 = SCMod3 = "IEC" and t...
by Jason.Jonkman
Thu May 06, 2021 7:40 am
Forum: Inflow Turbulence
Topic: TURBSIM wind field discontinuity
Replies: 9
Views: 264

Re: TURBSIM wind field discontinuity

Dear Mustafa,

It looks like this wind field was created with consideration of spatial coherence in the v- and w- components. This is a feature that can be enabled/disabled in TurbSim.

Best regards,
by Jason.Jonkman
Thu May 06, 2021 7:09 am
Forum: Computer-Aided Engineering Software Tools
Topic: VTK output to binary output
Replies: 16
Views: 1470

Re: VTK output to binary output

Dear Juan, The visualization functionality of FAST v8 and OpenFAST is implemented in the glue code rather than within each module. The visualization functionality makes use of input and output mesh data structures passed between modules to create the visualization data, e.g., reference positions and...
by Jason.Jonkman
Thu May 06, 2021 6:59 am
Forum: Airfoils
Topic: Inlet Velocity for DU 35 and DU 40 Airfoils
Replies: 7
Views: 91

Re: Inlet Velocity for DU 35 and DU 40 Airfoils

Dear Victor,

I'm not sure how you are calculating 109 m/s. With:

Re = u*L/nu

then:

u = Re*nu/L

I calculate u = 34.2 m/s with Re = 7E6, nu=1.464E-05 m^2/s, and L = 3 m.

Best regards,

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